Method and apparatus for control of an electric power distribution system in response to circuit abnormalities

ABSTRACT

A methodology and related system apparatus is provided for using and coordinating the use of information conveyed over communications to most efficiently and flexibly respond to abnormalities to reconfigure and restore service to end customers in commodity distribution systems in a manner to enhance the reconfigurability of the distribution system, e.g. circuit reconfiguration in an electrical power distribution system. Methodology is also provided to appropriately allocate system resources of the distribution system when so desired, e.g. to prevent the potential overloading of electrical power sources. In one illustrative arrangement, the methodology is characterized by resources at each node and communications of source allocation data or messages to other nodes to request and establish an appropriate allocation of system resources. In a preferred arrangement and especially useful for larger distribution systems, “teams” of nodes are defined in the distribution system having associated switching controls with the various teams communicating amongst each other to “negotiate” or work out the most efficient and expeditious reconfiguration of the system in response to fault conditions and other circuit abnormalities.

This application is a continuation of Application No. PCT/US03/33026filed Oct. 17, 2003 which is a continuation of and claims the benefit ofU.S. Provisional Application Nos. 60/421,180 filed Oct. 25, 2002,60/421/755 filed Oct. 28, 2002, 60/474,130 filed May 29, 2003, and60/474,349 filed May 30, 2003.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to improvements in control ofcommodity distribution systems, e.g. an electric power distributionsystem, and more specifically to the use of intelligent autonomous nodesfor isolating faulted sections of distribution lines, restoring serviceto end customers, improving circuit protection and allocation of systemresources.

2. Description of Related Art

In general, a distribution system comprises one or more sourcesconnected through a distribution network to one or more delivery points.As the commodity (material or energy) is transported through thenetwork, abnormalities (e.g., faults) may develop that can lead to adisruption of the normal flow of the commodity or a loss of thecommodity from the system. In order to help minimize the effects ofthese abnormalities, a distribution system will typically have nodes atvarious locations throughout the network which operate to monitor orcontrol the flow of the commodity through the system. It is desirable tonot only minimize the loss of the commodity when an abnormality occurs,but also to minimize the number of users who experience an interruptionof the delivery of the commodity due to any abnormality. In order toreduce the loss of the commodity, the nodes in a system may have thecapability to respond individually to system abnormalities withoutcoordinating with other nodes. In such a system, nodes can prevent thecommodity from flowing through the part of the distribution system wherethe abnormality exists. However, this system may interrupt service tomore users than is absolutely necessary.

The power distribution systems for which this invention is most usefulare generally of low to medium-voltage distribution feeders (rangingfrom approximately 4 KV to 69 KV) originating in power distributionsubstations and leading to the source of supply for end customers of anelectrical supply utility or agency. Although the electrical principlesgoverning operation of these feeders are identical to those governingthe operation of the higher voltage generation and transmission systems,the methodologies for building, operating and maintaining the lowervoltage systems are different. These methodologies are dictated by muchlarger quantities and geographical dispersion of distribution equipment,and by much lower quantities of electrical power supplied per mile ofcircuit. This creates requirements for lower cost, modular, standardizedequipment, which can be installed, operated and maintained with minimallabor and human supervision.

Failures of the distribution feeder (faults) occur due to downed powerlines, excavation of underground cable or other causes and are typicallydetectable by sensing excess (short circuit/overcurrent) current, andoccasionally by detecting loss of voltage. In distribution systems, itis sometimes the case that a loss of voltage complaint by the customeris the means by which the utility senses the outage, responding bydispatching a crew to isolate the fault and reconfigure the distributionsystem. The typical devices for isolating these faults are circuitbreakers located primarily in distribution substations and fuses locatedon tap lines or at customer transformers. The substation breakers aregenerally provided with reclosing relays that cause the breaker to closeseveral times after the breaker has detected an overcurrent conditionand tripped open. If during any of these “reclosures”, the fault becomesundetectable, service is restored and no extended outage occurs.Particularly on overhead distribution lines, temporary arcing due towind, lightening, etc causes many faults. Thus, the majority of faultsare cleared when the breaker opens and service is restored on theautomatic reclose. Alternatively, after some number of reclosureattempts, if the overcurrent condition continues to be present, therecloser goes into a “lockout” state which prevents further attempts toclear the fault.

Other than manually operated switches, most distribution feeders have noother means to isolate a fault between the substation and the fuses,thus any failure of the feeder results in lengthy, costly, inconvenientand potentially dangerous outages. The primary exceptions to thisinvolve the use of devices known as “line reclosers”, “interrupters” and“automatic line sectionalizing switches” or “sectionalizers”. These areautomatically operated devices, well known to those skilled in the art,and are referred to categorically in this document as “fault isolatingdevices”. The term “sectionalizer” refers to a specific family ofautomatic, fault isolating devices described below, while the terms“sectionalizing” and sectionalize” are used to describe the process ofisolating a faulted section of line, which can be performed by all ofthe classes of switches described above.

The “line recloser” is typically a pre-packaged, version of thesubstation breaker with reclosing relay. Line reclosers typicallyconsist of a fault-break switching device with integrated currentsensing, plus a control enclosure containing fault detection hardware,control logic, user interface module, and battery-backed power supply.When placed on the distribution line between the substation and customerloads, a line recloser is typically set up with fault detection settingscoordinated to operate before the substation breaker trips and tocorrespondingly prevent the substation breaker from tripping. This hasthe effect of reducing the number of customers affected by an end ofline fault. On very long feeders, the more sensitive settings can beused to protect the feeder from faults of a magnitude too low to bedetected reliably by the substation circuit breaker. Multiple linereclosers can be placed on a distribution line in series, although itbecomes increasingly difficult or impossible to coordinate theirsettings such that only the nearest recloser on the source side of thefault operates.

The “interrupter” is typically a pre-packaged breaker and fault relaywithout automatic reclosing capability. Interrupters are used primarilyin underground power distribution systems.

The “automatic line sectionalizer” or “sectionalizer” is typically aprepackaged combination of a load-break switch used in conjunction witha device known as a “line sectionalizer control”. The sectionalizersenses current (and optionally voltage) such that the operation of thecircuit and the source-side protective device can be monitored. Thesectionalizer is configured to open its switch under certaincircumstances when the circuit is de-energized after some number ofpre-configured voltage losses have occurred within a brief timeinterval. The circumstances vary from product to product, but are alwaysbased upon sensing of conditions caused by faults followed shortly byvoltage losses. Sectionalizers are designed to coordinate with theoperation of the circuit's protective devices. Typical sectionalizersare devices such as the Cooper Power Systems Sectionalizer type GV or GWmanufactured by Cooper Industries, Inc, or the EnergyLine Systems Model2801-SC Switch Control manufactured by S&C Electric Company.

Various types of distribution automation systems have been developed toisolate faults and reconfigure the distribution system to provideservice to the maximum number of end users. These types of systemsinclude various combinations of centralized controls, distributedcontrols and intelligent autonomous controls. In such centrallycontrolled systems, each node may communicate with a central controllocation which gathers information from each node and coordinates asystem-wide response. The central controller typically maintains adetailed map of the system topology, and this map must be updatedwhenever the system is reconfigured or new nodes are added. This canmake such centrally controlled systems less reliable and more difficultand costly to implement and maintain. Additionally, for small systemswith few nodes, the need to include a central controller cansignificantly add to the cost of the system. Furthermore, once anabnormality is rectified, the nodes typically must be transitioned to anormal state or to a specified state. Once the abnormality is corrected,it is generally desired to place the nodes in the original configurationor a specified configuration, at present this is typically donemanually.

Intelligent, distributed control methodology is illustrated in U.S. Pat.Nos. 6,018,449, 6,111,735, 6,243,244 and 6,347,027. While these systemsmay be generally suitable to perform their intended functions, it isadvantageous to determine how to optimally reconfigure a complexdistribution circuit while preventing overloading of any portion of thecircuit; i.e. allocation of system resources. This becomes particularlydifficult in circumstances where the circuit branches out (bifurcates)such that multiple load-side switches could attempt to simultaneouslypick up additional load and overload the circuit.

SUMMARY OF THE INVENTION

A primary aspect of the present invention is to provide methodology andrelated system apparatus for using and coordinating the use ofinformation conveyed over communications to most efficiently andflexibly respond to abnormalities to isolate faults and restore serviceto end customers (circuit reconfiguration); i.e. to enhance thereconfigurability of the distribution system.

In another aspect of the present invention, methodology is provided in asystem that responds to faults in a distribution system having aplurality of nodes to optimally reconfigure the distribution system andappropriately allocate system resources of the distribution system viaresources at each node and communications of source allocation data ormessages to other nodes to request and establish an appropriateallocation of system resources.

In a further aspect of the invention, “teams” of nodes are defined inthe distribution system having associated switching controls with thevarious teams communicating amongst each other to “negotiate” or workout the most efficient and expeditious reconfiguration of the system inresponse to a fault conditions and other circuit abnormalities.

These and other purposes and advantages of the present invention willbecome more apparent to those skilled in the art from the followingdetailed description in conjunction with the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a conventional distribution system in which nodes of anillustrative distribution system have been identified;

FIG. 2 is a block diagram of a node of an illustrative embodiment of thepresent invention.

FIGS. 3-8 are flow charts showing various routines employed by theembodiment of FIG. 2;

FIGS. 9 and 10 show alternate configurations of a distribution systemillustrating enhanced control features and improved fault isolationcapabilities, along with flow charts for supporting the configurations;

FIG. 11 shows a logical block diagram of an alternative embodiment ofnode controller 200, in which the circuit reconfiguration intelligenceis contained in an add-on microprocessor board;

FIGS. 12-14 show overall logical organization and the data structure ofanother alternate embodiment of the present invention;

FIGS. 15-21 are representations of system operation and response of theembodiment of the present invention of FIGS. 12-14 to an OvercurrentFault Event in an illustrative distribution system describing theresponse of the present invention to reconfigure and restore service;

FIG. 22, comprising FIGS. 22 a-22 g, is an illustrative flow diagramthat may be employed and representative of typical operations performedby the present invention of FIGS. 12-15 at a single team member;

FIGS. 23-55 are representations of system operation and response of thepresent invention of FIGS. 12-15 and 22 occasioned by the loss of asubstation identified as S1;

FIGS. 56-59 are illustrative logical flow diagrams that may be employedand representative of typical operations performed at a single teammember in accordance with source allocation methodology.

DETAILED DESCRIPTION

The present invention comprises novel improvements to a method andsystem for controlling a distribution system, e.g. an electric powerdistribution system. The following description is presented to enableany person skilled in the art to make and use the invention, and isprovided in the context of particular applications and theirrequirements. Various modifications to the preferred embodiment will bereadily apparent to those skilled in the art, and the generic principlesdefined herein may be applied to other embodiments and applicationswithout departing from the spirit and scope of the invention. Thus, thepresent invention is not intended to be limited to the embodiment shown,but is to be accorded the widest possible scope consistent with theprinciples and features disclosed herein. For example, the presentinvention is applicable to various distributed commodities in additionto electricity such as fluid flow etc. Further, while illustrativeelectrical systems utilize switch locations at various nodes andlocations, it should be realized that in particular embodiments, theseillustrative switch locations are any one of a variety of devicesincluding reclosers, breakers, sectionalizers or other protectivedevices.

FIG. 1 shows a simplified view of a portion of an exemplary electricalpower distribution system that can be controlled by the presentinvention. The distribution system comprises a plurality of sources ofelectrical power 102 connected to a plurality of users 104 (e.g.,factories, homes, etc.) through an electrical distribution line 106 suchas conventional electrical power lines. Distribution line 106 has aplurality of nodes 108 placed at predetermined points along the line106. The depiction of the number of sources, users, lines and nodes inFIG. 1 is arbitrary and there may be a different configuration or numberof each of these components in any given distribution system.

While the system disclosed in U.S. Pat. Nos. 6,018,449, 6,111,735,6,243,244 and 6,347,027 are well suited to making decisions based uponthe local configuration of, and sensed conditions on the maindistribution line, the present invention enables more efficient andflexible response to abnormalities especially in larger distributionsystems to reconfigure and restore service to end customers (circuitreconfiguration) and to allocate system resources such as to prevent theoverloading of electrical sources; i.e. to enhance the appropriatereconfigurability of the distribution system. For example, methodologyis provided via resources at each node and communications of sourceallocation data or messages to other nodes to request and establish anappropriate allocation of system resources. In a preferred arrangementand especially useful in larger distribution systems, “teams” of nodesare defined in the distribution system having associated switchingcontrols with the various teams communicating amongst each other to“negotiate” or work out the most efficient and expeditiousreconfiguration of the system in response to a fault conditions andother circuit abnormalities. In this manner, more intelligent localdecision making and inter-team coordination can be performed.

FIG. 2 depicts an illustrative embodiment of a node 200. Distributionline 202 passes through switch 204 which can open and close thedistribution line at this point. In other embodiments of the invention,the switch 204 can be replaced by other devices capable of performingpower sensing, control or conditioning functions such as voltageregulation (voltage regulators) reactive power control, (switchedcapacitor banks), fault sensing, etc.

It will be appreciated that consistent with the present invention, thenode 200 may also be of a type for controlling two (dual), three, ormore switches, with customer loads or alternate sources between theswitches. In this case, the distribution line 202 would pass through twoor more switches 204 which can open and close independently under thecontrol of the single node 200. In this context, node 200 is a singlenode from the standpoint of communications, but is multiple nodes fromthe standpoint of the power system and the control algorithms of thepresent invention. In this circumstance, the information flow isunchanged, but the communication step is simply bypassed.

Node controller 206 controls distribution switch 204. Node controller206 includes a control computer 208, a display 209, and an associatedmemory 210. Memory 210 stores the programming to control the node inresponse to sensed conditions and communicated information from othernodes and stores information about the system.

The present invention also includes features for team operation whennode 200 has protective (overcurrent protection/fault break)capabilities. Those skilled in the art will recognize that distributionswitch 204 can have different operating capabilities which may enhanceor detract from its ability to participate in circuit reconfiguration.For example, the lowest-cost switches may not be capable of interruptinghigh currents, or may not be outfitted with both voltage and currentsensors. Those skilled in the art will also recognize that node 200 maybe programmed not to open the switch under high interrupting currents(sectionalizing switch control), or alternatively may be programmed as a“circuit protective device” (recloser or breaker). When programmed as aprotective device, the switch is opened under overcurrent conditions(fault current) to prevent fire or damage to the circuit or to customerequipment, and also for safety concerns.

It is a primary aspect of the present invention to provide methods andapparatus in various embodiments having generalized algorithms andprocesses (see generally FIGS. 3-10, 14, 22 and 56-59) for using andcoordinating the use of information conveyed over communications toappropriately and optimally reconfigure the system in response tocircuit abnormalities and to allocate system resources. In this way,overall protection and reconfigurability of the distribution system or“team” is greatly enhanced.

Control computer 208 is connected to AC waveform processor 212. ACwaveform processor 212 is connected through field interface connector214 to distribution line 202. This allows the processor to measurevarious critical parameters of the electricity on the distribution linesuch as, voltage and current, digitally convert them, and send them tothe control computer for processing, communications, or storage inmemory.

Digital I/O interface 216 is connected to control computer 208, switch204 and distribution line 202. Digital I/O interface 216 allows computercontroller 206 to receive switch position sensing information and otherinputs, and to output control outputs to the switch.

Communications device 218 is connected to control computer 208 andallows it to communicate with other nodes on the system throughcommunications channel 110 of FIG. 1. The communications devices can beconnected to any communications network that is conveniently availableand has the desired characteristics; e.g. a Metricom Radio Radio (nowmanufactured by Schlumberger Industries and marketed under the Utilinet™product line) has been found suitable in one implementation. A second,optional, communications device 220 can be included in the node 200, ifdesired, for use by systems other than the present invention. An exampleof this would be a SCADA gateway.

Power is supplied to the node through power supply/battery backup 222.The battery can be charged from solar power, an AC potentialtransformer, or from power supplied through the voltage sensors.

Each of the nodes is connected to a communications channel 110. Any typeof communications channel can be used. For example, the communicationschannel could be telephone, radio, the Internet, or fiber optic cable.

In accordance with a first illustrative embodiment of the presentinvention as described in connection with FIGS. 3-8, FIG. 3 is a flowdiagram which illustrates the operation of a synchronization counter andstate selection process run by each node. In this process the nodesupdate their timer and database sequence counter which are used tosynchronize the nodes with each other. The nodes then check for errorconditions and set error flags if errors are found and determine fromtheir database which state they are in: synchronization, integritycheck, or reconfiguration event. An enhancement to the synchronizationprocess is the addition of step 315 to provide protective devices with“advance notice” of their protective characteristics prior to areconfiguration even such that initial restoration of the circuit maybegin prior to adjustment of protective device profiles if the priorsettings are adequate.

FIG. 4 is a flow diagram which illustrates the operation of thesynchronization process state run by each node in accordance with thepresently preferred embodiment. In this state the nodes construct adatabase of critical control information about the distribution system.All nodes contribute to the construction of a database. Each node storesin its memory a copy of the database. The steps in constructing thedatabase in accordance with the presently preferred embodiment are asfollows: each node receives the database from the previous node, addsits own record of information and passes the database on to the nextnode. This process continues until all nodes have received a record fromevery other node. Once this process is compete, each node then proceedsto the integrity check state shown in FIG. 5

FIG. 5 is a flow diagram which illustrates the operation of theintegrity check state process run by each node. When a node runs thisprocess, it checks the records it has received from all the other nodesto ensure that the records reflect a timely version of the state of thesystem.

FIG. 6 is a flow diagram which illustrates the operation of the transferprocess state. This flow diagram describes the process used by each nodeupon the occurrence of a fault in the system followed by standalonesectionalization. This process is also started in a node when the nodereceives a message that another node has entered this process. In orderto restore electric power service to as many users as possible after afault has occurred, each node will use this process to determine if itcan close its associated switch(es). These features extend thefunctionality of the transfer logic to insure that the protectionsettings match the requirements of the transfer (steps 645-654).

FIG. 7 describes the logic used by each node to return the distributionsystem to its normal state once the fault has been cleared. This extendsthe functionality of the return-to-normal logic to insure that theprotection settings match the requirements of the return-to-normaltransition, particularly when the “closed” transition is used (steps 722and 750-752).

FIG. 8 is a flow diagram which illustrates the operation of a task timerthat is used during the transfer process state of FIG. 6 and the returnto normal process state of FIG. 7 in order ensure that the system doesnot take too much time to complete the steps required in either of theseprocesses. This extends the functionality of the return-to-normal logicto reset the protection settings when the return-to-normal transition,and in particular when the “closed” transition return-to-normal is used(steps 830-831).

In accordance with this first illustrative embodiment, memory 210 storesthe programming to control the node and stores a database of noderecords about each node in the system (team database). Each recordincludes a number of fields which include information that allows thenode controller to control the node's switch(es) to alter thedistribution line characteristics in response to distribution systemdemands. In particular implementations, the record includes protectivecharacteristics, facilitating coordination of protection settings duringload transfer/restoration.

In the illustrative embodiment, the ordering of the node records in thedatabase corresponds to the physical ordering of the nodes in thedistribution system. It would not deviate from the present invention tohave the node records in the database ordered in some other fashion andto include information in each node record of the node's actual orrelative physical position in the distribution system. If the nodecontroller is of a dual or multiple switch type, the position of eachswitch is represented in the database and may be ordered independently.

In another embodiment of the present invention, a single, dual ormultiple switch node from the standpoint of communications can be usedas the only member of the team. A dual switch node may act as the onlymember of the team when it is the only member physically installed(other members may be installed later), when other members of the teamhave been temporarily removed from the team, or when errors at othernodes in the team prevent the entire team from acting upon an outagecondition.

Also, the present invention is suitable for controlling a loopdistribution system as in FIG. 1 in which there are two sources and anormally open switch (a “tie” switch) in the distribution line betweenthe two sources, or a radial distribution system in which there is onesource and no tie switch. It would not deviate from the presentinvention for the database to represent simpler or more complexdistribution system topologies and for the invention to be able to workon such topologies.

In particular implementations, the tie switch can close to restore load(backfeed) from either side, depending on which side of the switch isenergized and which side is deenergized. As a convention, the circuit isdescribed as having a “right” side and a “left” side, with the tieswitch between the right and left sides. The lowest numbered node isdesignated as being closest to the source on the left side of thecircuit, and the highest numbered node as being closest to the source onthe right side. The circuit traversed between each of two adjacent nodesis referred to as a “transfer segment” or “segment”.

In the illustrative embodiment of the invention, each node's databaserecord includes: (1) record currently in use flag, (2) indication of thetype of device represented by each individual record, (3) the node'scommunication address, (4) its normal switch(es) state(s) (open orclosed), (5 present switch(es) state(s), (6) the voltage state (isvoltage present on the line or not)(by position if applicable), (7) thefault state (has a fault been detected)(by position if applicable), (8)the present time stamp (9) the database sequence number, (10) the logicprocess state (what state and step is the switch in), (11) errorcondition status flags, (12) automatic/manual operation mode status (byposition if applicable), (13) average of the sensed loads on each phase(by position if applicable), (14) time stamp at start of event process,(15) indication of method of return to normal (open or closedtransition), (16) indication of whether the node was within the affectedportion of the circuit, (17) maximum number of segments that can beadequately protected with the current protective settings when feedingthe circuit from the left side, and (18) number of segments that can belikewise protected when feeding the circuit from the right. For thepurposes of this illustrative emboidment, a segment (see items 17 and 18above) represents the distribution line between two adjacent team nodesof FIG. 1. In the case of a single communication node containing dual ormultiple switches, the number of segments counts the load between anytwo switch positions along the main distribution line as an additionalsegment. The “maximum number of segments” is obtained using amethodology outlined below. It will be appreciated that in otherimplementations of the invention different node data may be stored inthe database record for each node without departing from the scope ofthe invention.

The team local record database (above) allows each node to have enoughinformation about the state of the distribution system to intelligentlycontrol its local switch. Additionally, since the database is locallystored in the node, the node need not ask other nodes for information orwait to receive operating instructions from other nodes.

It will be appreciated that consistent with the present invention therecord currently in use flag can be used to remove a node fromcoordinated system activities or allow a node to resume coordinatedsystem activities. The decision to remove or resume activity of a nodemay be made by, but is not limited to an external decision makingentity, or by the node itself.

Protection Profiles and the Team Database

The present invention includes the representation of additionalattributes in the protective device profiles. These attributes enhancethe ability of the protection engineer to convey the intended operatingrange or purpose of the settings to the team nodes. In addition, theseattributes support additional, team-related functionality not otherwiserepresented in the protection settings of the individual device as willbecome clear below. The attributes are: (1) “Profile Type” Indicates theintended use of this profile. For the preferred implementation, thepossible values are: (a) “Team Mode/Normal” for use when the nodes arein their normal operating state, with the normally open switch open, andall others closed. In the preferred embodiment, there is only one TeamMode/Normal profile, although it would not deviate from the scope ofthis invention to have multiple profiles, selected dynamically basedupon operating parameters such as the season of the year or load-basedcriteria. (b) “Team Mode/Transfer” for use in circumstances whereadditional segments or load must be picked up or carried at this deviceand the normal profile is inadequate. There may be multiple TeamMode/Transfer profiles, selected for use based upon various selectioncriteria discussed below. (c) “Standalone” when team operation is notenabled, or is temporarily disabled due to persistent errors or problems(these are referred to below as “Stop Transfer” conditions). (d) “TeamMode/Return to Normal” for use during a “return to normal” teamoperation (see below). (2) “Number of Segments, Left-Side Distribution”Indicates the maximum number of additional segments, beginning at thelocal switch position, that can be protected by the profile when poweris being fed from the left hand side of the circuit. This number mayassume a value greater than the direct reach of the device if the systemincludes other protective devices with profiles that protect the end ofline. In this case, if the other devices are team members, one of thefeatures of the present invention is to maintain consistency among theprofiles. (3) “Number of Segments, Right-Side Distribution”: As above,but for power fed from the right side. (4) “Maximum Load” Indicates themaximum amount of customer load that the profile is intended to protect.This value is typically predefined by the user and compared against realtime load data to insure that the profile is not used in circumstanceswhere false tripping of the protective device could occur. (5)“Protection Selection Key”: This is an index or internal pointer to theactual configuration settings associated with the profile. This indexallows the user-specified entries to be linked to a collection of devicesettings either preloaded in the device or maintained as a separatedatabase. Those skilled in the art will be able to appreciate otherattributes and attribute values that could be used to characterize theconfiguration of protective device settings.

It is an object of the present invention to to decide whether or not theprotective settings of other team members require adjustment beforeadditional load can be picked up by closing open switches. Thus, the“number of segments” fields in the local record must be locallydetermined and shared between team members. This process takes placeperiodically during normal operation whenever the team database isexchanged (“sync” process, FIG. 3, Step 315). A more complex process isinvolved in determining the values for the fields during errorprocessing and/or transfer events and is discussed below.

Calculating the “Number of Segments” Field—Normal Operation

The discussion below identifies the way that the “number of segments”fields are calculated for the presently active profile during normalteam operation exclusive of transfer and return-to-normal events orerror handling. Thus, protective devices operate without team-invokedchanges to their operating profiles unless a transfer or certain errorconditions are present. It would not deviate from the scope or intent ofthis invention if changes to the active profile were made andcoordinated throughout the team based upon seasonal variations, load orother sensed or conveyed information.

There are many possible ways for deriving the “number of segments”fields in the local record of the team database based on the type andcapabilities of the device. The following Illustrative methodology isbased upon the switch and control's inherent capabilities:

Sectionalizing Switch: On initialization, the number of segments thatcan be protected is set to an indefinitely large number. When the teamdatabase or local record is transferred (during synchronization orduring a transfer event), the count is reduced to the number of segmentsprotected by the sectionalizer's source-side nearest adjacent node,decremented by one. For example, for the local record corresponding tothe second node, if the first node can protect three segments on itsload side when power is distributed from the left (left-side segmentcount), and the second node is a sectionalizing switch, it sets itsleft-side distribution segment count to two. If the third node's localrecord indicates that it can protect two segments beyond its positionwhen power is distributed from the right, the sectionalizing switch atnode two sets its right-side segment count to one. Special provisionsmust be made for the first node (left-hand distribution) and last node(right hand distribution), since they have no source side nodes. Threeoptions are supported in the illustrative embodiment for conveying thesource-side segment count to the terminal (preferred and alternatesource) nodes: (a) the count can be predetermined (configured) basedupon worst-case loading protection studies for the circuit as seen bythe source side protective device, (b) it can be predetermined to anarbitrarily high value (to defeat the prevention of additional circuitloading based upon inadequate segment count), or (c) it may be acquiredover communications from the source side protective device (see sidelineteam member functionality below). The provisions above also apply whenthe terminal nodes are protective devices rather than sectionalizers(see below).

Protective Device (Recloser or Breaker): Based on the protectivesettings of the device and the sophistication of the control, the numberof segments may be configured or dynamically calculated based in part onthe capabilities of the node as described below.

In the illustrative embodiment, the breaker or recloser's active profileattributes are used in the derivation of the “number of segments” fieldsin the node's local record. The number of segments is calculated as thelesser of the number of segments protected by the source-side adjacentnode (minus one), or the number of segments that can be protected basedon the local device's active profile (the profile currently in use). Inthe later case, the most-recent load data stored in the team's localcopy of the team's database is used to determine whether or not thepotential, calculated load (based on real-time load data) correspondingto the number of segments handled by the profile exceeds the maximumload configured for the profile. If it does, the “number of segments”for the profile is reduced until the load can be handled. The logic formaking this calculation must be sensitive to the load measured locally,as well as to the direction of present current flow (left or right), andthe present measured load of each individual segment on the oppositeside of the normally open switch. For example, for calculation of thenumber of segments for left hand distribution, if the count extends theprotection one segment beyond the position of the normally-open switch,the measured circuit load at the switch to the right of the normallyopen switch would be added to the locally measured load for comparisonwith the profile. It will be appreciated by those skilled in the art,that the reduction of segments based upon load can be defeated if theend user configures an arbitrarily high value of the load current thatcan be carried through the node with the specified profile.

Selecting Profiles During Load Transfer or Error Processing

This process is invoked whenever the number of segments handled by thepresently active profile is recalculated during a load transfer,return-to-normal, or error processing or recovery event. Updates to theteam database during these events trigger a profile search/selectionprocess. The process identified below is a simplified approach forselecting the appropriate profile, although it would not deviate fromthe scope of this invention to use a more elaborate process based oncalculations of line impedance, line loading or other factors, or totrigger the selection process based on different events.

In the preferred embodiment, the events that trigger the selectionprocess are: (1) Completion of a synchronization interval (see below)with no errors and a transition of the circuit configuration into its“normal” state, with all switches in their correct normally closed oropen positions. This event causes the “Team Mode/Normal” profile to beselected. (2) Transition to a team “stop transfer” condition whichcauses selection of the “Standalone” profile, assuming the last knownconfiguration of the circuit was such that all switches were in theirspecified “normal” positions. (Note: Other errors do not alter theselection of the presently active profile.) (3) Transition to the“return to normal” state (see below) causes selection of the “TeamMode/Return to Normal” profile. (4) During a transfer event (see below),detection that a transfer is in progress, and the maximum number ofsegments that the local switch will have to handle is greater than thenumber handled by the presently active profile.

In this latter circumstance, in the illustrative embodiment, the nodescans through the list of “Team Operation/Transfer” profiles searchingfor the first entry that can carry the maximum number of segments andpre-fault operating load. This allows the profile reselection process tooccur at most, only once during typical transfers. It would not deviatefrom the scope of this invention to provide the nodes with additionalinformation during the notification process regarding the location ofthe fault such that the profile selection could be more closely matchedto the requirements. In addition, it would not deviate from the scope ofthis invention for the selection process (and associated communications)to be carried out each time a segment was picked up.

If the selection process above results in the need to change the actualprotection settings or operating mode of the protective device, thechange is initiated and verified. Only after positive verification isthe local record in the team database updated. If the verificationfails, an error condition is generated, and the logic reattempts theselection. If a transfer is in progress, this is repeated indefinitelyuntil the transfer process times out.

Free Running Counter

Steps 310 to 318 of FIG. 3 comprise a synchronization routine that isoften called by steps in other processes run by a node, especially whena node is waiting for a specified event to occur. In step 310 the node'sfree running tenth counter is incremented. A free running counter isused to establish a reference for time stamped logic. As will be seenshortly, these counters are used to ensure synchronization among thenodes. In step 312 the node checks the free running counter to determineif it has reached its maximum. When the maximum count is reached, thesynchronization interval expires. If the synchronization interval hasexpired then step 314 is executed and the sequence number for thedatabase recorded by the node is incremented and a time stamp isrecorded in the node's database to help ensure synchronization. As animprovement provided by the present invention, at step 315 theillustrative embodiment also calculates/recalculates the “number ofsegments” fields for both right hand and left hand distribution usingthe methodology shown above. The database sequence number is increasedby one count on each synchronization interval and each node includes thedatabase sequence number in its local record.

The database sequence number at each node should be the same if all ofthe nodes are properly functioning and synchronized. Therefore, theinclusion of each node's database sequencing number in its record allowsnodes in the present invention to be certain that the data beingreceived from other nodes is timely and reliable. In this way each nodecan ascertain for itself whether the system as a whole is functioningproperly.

After step 314, or if the synchronization interval has not expired thenthe node checks to determine if communications are allowed.Communications will be prevented in certain situations. An example ofwhen communications are not allowed in a illustrative embodiment is whena team of nodes is initially being configured, all other nodes must besilent except for the node distributing the configuration information.If communication is not allowed for the node, then the node returns tostep 310 and is in effect on its own for the moment.

If communication is allowed then step 320 is executed. The node willcheck for errors and events and set a flag if an error or event isdetected. Then each node determines which of three states it is in:synchronizing, integrity check, or reconfiguration event. Each nodedetermines on its own, independently of the other nodes, which of thethree states it should be in based on its own internal sensors and thedatabase records that it has received from the other nodes. Typically,all nodes will be in the same state unless the system is transitioningfrom one state to another. However, any particular node can only be inone state at a time.

Synchronization Process State

If the node is in the synchronization process state then it follows theprocess illustrated by the flow chart in FIG. 4. At step 412, the nodemust determine if it is the first active node. In a illustrativeembodiment of the invention the node just after either source can beconfigured to be the first active node in the database and the othernode would be the last active node in the database. The nodes in betweenwould be ordered in the database to reflect their physical ordering inthe distribution system. It would not deviate from the present inventionto have the nodes ordered in the database in an order other than theirphysical order and to include data in each node's record that allows thenode's absolute or relative physical ordering to be determined.

The first node will proceed to step 414 and will start the process ofconstructing the database of records for the nodes. The first node willput its local record in the database and then send the database to thenext node listed in the database. This database is called the “ball” asit is sent around the system from node to node. The record added to thedatabase by each node contains the 18 items of information listed abovefor the currently passing node.

Although there are many possible ways that this database could beconstructed and communicated, the present incarnation of the inventionconstructs the database by sending it to each successive node to havethat node's record added onto the database. The database could beconstructed in other ways without deviating from the present invention.For example, each node could simply broadcast its record on thecommunications channel for reception by all other nodes.

The first node will then continue on to step 418, and since the node hasnot yet received the ball twice, it will continue on to step 420. Instep 420, the node determines if it is time to exercise its link. A nodeexercises its link by signaling another node to signal it back. Thisallows a node to determine if its communications system is working. Todetermine if it is time to exercise its link, a node checks thesynchronization interval timer to determine if the synchronizationprocess has taken more than a predetermined used defined period of time.This prevents the node from getting stuck in this state if there is acommunications failure.

If it is not time to exercise the link, the node next goes to step 422.In this step the node executes steps 310 to 318 of FIG. 3 and checks forerrors and events. If an error or event is detected, a flag is set and,if necessary, the process that is active is ended. This is called a“synchronization and error checking loop.” Once this is completed, thenode returns to the synchronization process and proceeds to step 424 andchecks to determine if it has received the ball. When thesynchronization process is run by nodes other than the first node, theygo from step 412 directly to step 424.

At step 424, if the node has not received the ball, it will return tostep 420 and continue this cycle until it is either time to exercise thelink or the ball has been received. If the ball is received then thenode goes from step 424 to step 426. At step 426 the node includes itslocal record with the ball and sends the ball on to the next device.(The last listed node will send the ball to the first listed node.) Thenode proceeds to step 418 and checks whether it has received the balltwice. If not, then the node proceeds to step 420 again and continues inthat loop.

When the ball is received the second time, the node goes from step 424to 426 to 418 and then to step 428 and schedules a link exercise messageto another node in order to test the communications link to ensure thatit is working. This is the same step the node jumps to if the time toexercise the link counter in step 420 expires.

After the node has exercised its communications link in step 428, thenode goes to step 430 and checks the integrity check counter todetermine if it is time to enter the integrity check state asillustrated by the flow chart in FIG. 5. If it is not yet time for thenode to enter the integrity check state, then the node will proceed tostep 432 where it performs a synchronization and error checking loop.The node then cycles back to step 430 and will continue this loop untilit is time for an integrity check.

In a illustrative embodiment of the invention, the synchronizationprocess occurs once per predetermined interval. The length of thepredetermined interval is based on the number of nodes in the system.This interval could be larger or smaller, or based on something otherthan the number of nodes in the system, without deviating from thepresent invention.

Thus, the synchronization process illustrated by the flow diagram inFIG. 4 periodically updates the information in each node's database.This process allows each node to contain up to date information on thestatus of all the other nodes.

Integrity Check State

FIG. 5 shows the flow chart which illustrates a process employed for theintegrity check state. In this state, each node checks to ensure thatthe database records contained in its memory appear to be synchronized,that there are no error conditions, and that the nodes are in thecorrect states. In step 512 the node checks the database sequencenumbers to ensure that they all match. In this way, the node can ensurethat the records in the database from each node are all from the samesynchronization process.

If the sequence numbers do not match, then the node goes to step 514 anda flag is set for the sequence numbers to be reset to re-synchronizethem. This error flag will prevent any coordinated team activities fromtaking place until another synchronizing interval has taken place andthe database sequence numbers match.

If the sequence numbers match, or after the flag has been set in step514, the node then continues on to step 516. In this step, the nodechecks each of the database records to ensure that they were all timestamped within one second of each other. This requirement ensures thatthe records in the database accurately reflect a picture of the systemat roughly one point in time. If the records are not time stamped withinone second of each other, then the node goes to step 518 and sets a flagfor a new time stamp. This flag will not allow synchronized teamactivities if the time stamps are out of synchronization with each otherby more than a predetermined amount set by the user. In one embodiment,if the time stamps are 5 seconds out of synchronization then an errorflag is set. It will be appreciated that the allowable discrepancy ofthe time stamps is an implementation dependent parameter.

In the illustrative embodiment of the invention, this strictimplementation of the integrity check could be considered a “safe mode.”It will be appreciated that consistent with the present invention othermodes may exist that would allow the continued operation of teamactivities even with various levels of integrity check failures.

If the time stamps are not flagged as being out of synchronization, orafter the flag has been set in step 518, the node then proceeds to step520. In this step, the node checks for stop transfer errors, and if anyexist, it tries to determine if the error can be cleared. Examples oferrors are: (1) an out of synchronization error in which the databasesequence numbers for the nodes do not match, and (2) a reconfigurationprocess occurred and was unable to be fully completed due to externalconditions such as a malfunctioning switch.

If the error can be cleared then a flag is set in step 522 for the errorto be cleared. The node then continues on to step 524. In this step, thenode determines if it is all ready for transfers. After areconfiguration event, the node must make sure that all of the nodes aresynchronized and that other necessary conditions are met. For example,in one embodiment, the node checks its database to determine if all ofthe nodes have an average 3 phase load that is within a predetermineduser defined limit. If the node determines that it is all ready fortransfer, then it will go to step 526 and set a flag indicating that itis all ready for transfer.

Next, the node goes to step 528 to determine if it is in the correctready state. Each node can be either ready for a transfer process orready for a return to normal process, and all nodes should be in thesame ready state. In this step, the node will compare which ready stateit thinks it should be in based on its local information and the statethat other nodes are in based upon information in the database. If thenode is not in the correct ready state then it goes to step 530 anddetermines the correct ready state and changes to it.

The node then proceeds to step 532 where it checks to determine if thereis a return to normal mode mismatch. In this step the node checks tomake sure that all of the nodes are set to the same return to normalmode: open transition, closed transition, or function disabled. If allthe nodes are not set to the same return to normal mode, then, there isa mismatch and at step 534 an error flag is set. Next, the node returnsto step 310 in FIG. 3.

Transfer Process State

The transfer process state flow diagram of FIG. 6 will be described withthe aid of a simple example. Referring to FIG. 1, assume a faultdevelops in distribution line 106 between nodes 108A and 108B. Asdescribed above, typical electrical distribution systems will haveeither a breaker or a recloser (reclosing breaker) at the source ofsupply for safety and for protection of the circuit. Utilizing thesystem disclosed in U.S. Pat. No. 6,018,449, sectionalizers may beplaced at switch locations 108A-F as shown in the FIG. 1. The“sectionalizer” described here is based on the EnergyLine Model 2801,with additional features added to support operation under a illustrativeembodiment of the invention. The standard sectionalizer logic will open(trip) the switch if: 1) its sectionalizing logic is enabled and thedevice is operational, 2) a pre-configured number of voltage losses(typically 1-3) on all sensed phases have been counted within a brieftime period (typically 45 seconds), 3) an overcurrent condition wassensed just prior to the first voltage loss, and 4) the switch ispresently closed. An additional option in the conventional softwareallows the switch to trip if voltage, sensed on all three phases,becomes grossly unbalanced, and remains unbalanced continuously for aconfigured time period (typically 30 seconds).

It will be appreciated that consistent with the present invention the“sectionalizer” described here may be one of many types, including butnot limited to multi-switch operators, fault interrupting switches, andair-break switches, without deviating from the intent of the presentinvention. For the purpose of this example, the single switchsectionalizer described here will be used.

An optional feature that can be provided in a illustrative embodiment ofthe invention causes the switch to open on a configured count of voltagelosses even if a fault was not sensed just prior to the loss of voltage.This allows the first step of isolating both sides of the faultedsection of line to be executed immediately without communication toother devices. Another optional feature causes the configured count onvoltage losses (subsequent to sensed faults) to be dynamicallycalculated locally based upon the position of the switch relative to thepresently designated open tie switch. Configuration parameters allowthis dynamically calculated range of counts to be further constrained bythe user to always fall between a minimum and maximum number. Anotheroption allows the switch to open after a single extended voltage loss.Finally, the counting of faults followed by voltage losses can beconfigured to count each event as a fault either: 1) if the firstvoltage loss was preceded by a fault, or 2) if all voltage losses werepreceded by faults.

Another unique feature of a illustrative embodiment of the invention isits modified one-shot-to-lockout capability. If a switch is closed aspart of any automatic operation (or manually closed by a humanoperator), some sectionalizers, including the EnergyLine Model 2801-SC,can be configured to automatically re-open the switch if a voltage lossis detected during a brief interval following the operation (typically 5seconds). A illustrative embodiment of the invention has the additionalcapability to avoid opening the switch until two counts of voltage losshave been detected. This becomes a benefit when the circuit's breakerreclose pattern includes an initial instantaneous close operationfollowing a trip operation due to a fault.

Those skilled in the art will recognize that consistent with the use ofautomatic line sectionalizers at each switch location, reclosers couldalso be substituted such that the switch was opened/operated one or moretimes under load to clear the fault. Although this would requiremodifications to the prepackaged, commercially available recloserproducts to support the team coordination functions, comparablefunctionality to that provided by the sectionalizer could be achieved.It should also be noted that a variation of the one-shot-to-lockoutcapability implemented in the sectionalizer implementation is availablein many reclosers as the “block reclose” option. The challenge with theapproach of substituting reclosers for sectionalizers, as mentioned inthe introduction, would be to coordinate the protective settings ofthese reclosers to prevent excessive switching or tripping/lockout ofthe wrong device. It is an object of this invention to provide the meansto minimize or eliminate this possibility. If the power distributionsystem of FIG. 1 contains an automatic sectionalizing device, then afterthe fault occurred between nodes 108A and 108B on distribution line 106,the device, depending on how it is configured, would cause switches inany one or all of nodes 108A, 108B and 108C to open causing all users104A, 104B, and 104C that are down stream from an open switch to loseservice.

In one implementation of the invention, the sectionalizing logic will beset up to open all switches between the fault and the normally open tieswitch 108G. This allows the present embodiment of the invention toreclose switches one at a time to gradually increase the load seen bythe distribution system to aid the system in resuming service to users.Once any node has finished sectionalization the node enters the transferprocess state illustrated in flow diagram of FIG. 6 in which a node willattempt to close its switch. Also a node will enter the transfer processwhen it receives a communication that another node or team of nodes hasentered the transfer process.

Without departing from the present invention, the transfer process statecould be initiated by an event other than finishing sectionalization.Depending on the type of distribution system and its needs andcharacteristics, it may be desirable to have other events trigger thesystem into action. For example, it may be desirable to have the systemtriggered into action by detection of a serious under or over voltagecondition.

Each node is continually updating the record in its database concerningits own status information. Thus, while the records in the databaseconcerning all other nodes, the ball, is sent to each node only in thesynchronization process state, each node maintains an updated record onits own status.

For the purposes of this example, assume that sectionalization hascaused the switches in nodes 108A, 108B, and 108C to open resulting inusers 104A, 104B, and 104C all losing service. Once sectionalization hasended, each of the three nodes 108A, 108B, and 108C will independentlybegin the transfer process state, because they each have undergonestandalone sectionalization.

When a node enters the transfer process state depicted in the flow chartof FIG. 6, the node executes step 612 and starts the end process timertask. This timer ensures that the nodes do not spend too long trying tocomplete the task. Should something prevent the node from completing thetask in the allotted time, the timer will end the transfer processstate. Each node will use the same start time for its timer as the nodethat first initiated the transfer process. In this way, all nodes in thetransfer process will “time out” at the same time. The operation of thistimer and the task it calls are shown in FIG. 8 and will be discussedbelow.

The length of the timer can be set by the system operator to meet theneeds of the particular system being controlled. For example, to ensurethe safety of repairmen working on the power lines after a fault hasoccurred, the timer could be set to remove the nodes from the transferprocess a known period of time after the fault occurred. In this way,even if the conditions in the transfer process state are met which wouldhave allowed a switch to close and energize a power line, repairmen whohave begun to service the system are not put in danger because thetransfer process has timed out and the switch will not close.

In a illustrative embodiment of the present invention, each of thesethree nodes enters the transfer process on its own, triggered by its ownlogic, stored data and sensor readings. The presently illustrativeembodiment of the invention does not require central control,communication, or approval for any of the nodes to enter this state.

Once the timer has been started, the node proceeds to step 616 anddetermines if the switch it is controlling is closed during the normaloperation of the distribution network. Referring to FIG. 1, switches108A, 108B, 108C, 108D, 108E, and 108F are closed during normaloperation of distribution system, and switch 108G, a tie switch, is openduring the normal operation of the system. Since switches 108A, 108B,and 108C are each normally closed during the operation of the system,these nodes will continue on to step 618. At step 618 each of the nodesthat has entered the transfer process state will transmit its updatedrecord to the next active node listed in the database and the previousactive node listed in the database. These two nodes are called the“nearest neighbor” nodes. Node 108A will transmit to node 108B, node108B will transmit to nodes 108A and 108C, and node 108C will transmitto nodes 108B and 108G. In this way each switch that has entered thetransfer process state will inform its nearest neighbors of itsprogress. It will be appreciated that, although the illustrativeembodiment employs communication between “nearest” neighbors,alternative embodiments may employ different node-to-node communicationpatterns consistent with the invention. Thus, in accordance with theillustrative embodiment of the invention, each node can inform othernodes of its state regardless of the physical layout of the distributionsystem or the physical deployment of the nodes.

It will be appreciated that if the node is a multi-switch node, for thepurpose of the transfer process only, a “nearest neighbor” may be one ofthe switch positions within the node itself. In the illustrativeembodiment of the invention a nearest neighbor database is assembledfrom the information contained in the internal team database. Thetransfer logic is then executed using the information in the nearestneighbor database. If the node is a multi-switch node, separate nearestneighbor databases will be constructed for each switch position. In thepresent example, the nearest neighbor database consists of informationfrom the local node and the two nodes that are physically adjacent toit.

When node 108G receives the communication from node 108C, node 108G willstart the transfer process state. In general, when one node receives acommunication from another node that the other node has entered thetransfer process state, the node receiving the communication will itselfenter the transfer process state. This procedure allows the system toself organize, eventually putting each node of the system into thetransfer process state without requiring any communication from acentral office or any interaction with a human.

Thus, in the illustrative embodiment, there need not be any centralizedcontrol or logic center to decide what actions are appropriate for eachnode to undertake at a given point in the process. Each node of thepresent invention can operate based only on its sensors and thecommunicated information. Due to this simple operating structure, thepresent invention can be easily expanded or reconfigured by simplyreordering the nodes in the database without the need to change theprogramming or logic of the present invention. For example, to add a newnode between nodes 108B and 108C of FIG. 1, the system operator wouldphysically insert the new node into the system at the appropriate placeand program it into the database between nodes 108B and 108C. This isaccomplished by moving the records for all of the nodes in the databaseafter node 108B down one space and inserting the record for the new nodein this newly created space in the database.

Node 108G executes step 612, starts the end transfer process timer, setsit to end at the same time as the node(s) that initiated the transferprocess, and then goes to step 616. Since node 108G controls a switchthat is normally open it will go to step 638. At step 638 node 108G willobserve its sensors, the information in its database, and theinformation sent to it by node 108C to determine whether it can close.In the illustrative embodiment of the invention, the conditions listedin Table 1 are checked by the node in order to determine if it canclose. The conditions used at step 4 in Table 1 are shown in Table 2.Other sets of conditions could be used without departing from theinvention.

Table 1

In order to close the normally open switch associated with a node, onevalid closed switch and one valid open switch must be detected as theadjacent switches associated with adjacent nodes on either side of thenormally open switch. The following rules define the conditions thatmust be met for the normally open switch to validate the state ofadjacent switches.

A normally open switch on the load side of a faulted line section mayclose for the purpose of restoring load if:

-   1. no error conditions exist-   2. the adjacent fault side switch is open-   3. the adjacent fault side switch did not detect a fault, but did    see a loss of voltage-   4. the current level seen by the adjacent fault side switch before    the outage is within the bounds set in the local switch (The    conditions used in this step are shown in Table 2.)-   5. the adjacent non-faulted side switch indicates it observed a    voltage loss and/or fault but it is now closed, or the adjacent    non-faulted side switch is the normally open switch, or the adjacent    non-faulted side switch is a breaker and voltage has been restored    (this step is bypassed if the local switch is the normally open    switch, no team reclosers exist on the alternate feeder, and voltage    checking is disabled)-   6. the “number of segments” that can be picked up is greater than    zero. For this test, the number from the local record of the team    database corresponding to the non-faulted direction of supply (left    or right) is used.-   7. good voltage is detected on its voltage sensors (this test is a    user-configurable option).-   8. the adjacent switches are in the proper logical operation step

Table 2

(This Table elaborates on step 4 in tables 1 and 3)

In order to determine whether load may be restored during a transferprocess, the process uses the total load to be transferred compared tothe capacity of the alternate circuit. Three basic set points are usedby an engineer to limit transferred load. They are:

-   -   Capacity for Transfer (total feeder load N/A)    -   Maximum Capacity for Transfer    -   Maximum Rated Feeder Capacity        All three set points have settings for the left feeder and the        right. All three also have summer and non-summer season        settings.

The transfer process utilizes, if available, the real time total load onthe associated feeders. This real time total load value may come overcommunications from any source such as a substation RTU.

The two set points that work with this process are the “Maximum Capacityfor Transfer” and the “Maximum Rated Feeder Capacity”. The “MaximumCapacity for Transfer” is the configured amount of load that may betransferred to an alternate feeder when that feeder is lightly loaded.The “Maximum Rated Feeder Capacity” is used in combination with theactual real time load. The difference between these two is the presentreal time capacity the alternate feeder can handle. In order for atransfer to occur, the load that was reported to exist before thereconfiguration event began by the next open switch must be less thanboth the present real time capacity and the “Maximum Capacity forTransfer”.

The real time load must be sent to the switch controls at least onceevery 20 minutes. After 20 minutes past the last reception of real timeload the value goes to undefined. An undefined value causes the fallback process to take affect. This prevents old load data from allowingtransfers to occur when the source of this data fails to report it.

The fall back process uses the “Capacity for Transfer (total feeder loadN/A).” This value is intended to be a conservative value. Whenconfiguring this value the engineer should take into account averageloading, peak loading, and the emergency load capacity on the alternatefeeder. The engineer should feel comfortable that a transfer of thisamount of load can occur at any time and still be accommodated by thealternate feeder.

Note that the process for the two feeders is independent. Real timeloading data may be provided for one feeder while the other feeder usesthe conservative transfer process.

Assume that all of the conditions are met to allow the switch at node108G to be able to close. Through the use of the conditions listed inTables 1 and 2, the node can determine on its own whether or not it canclose its associated switch. Additionally, only one message had to besent to enable node 108G to act to restore service—the message from108C. In the illustrative embodiment of the present invention, and inthe case where the team includes protective devices such as breakers orreclosers, the normally-open switch is thus closed with the additionalassurance that the protective settings of all of the source-side teammembers have been preselected to handle the additional load. If theconditions were not met to allow the switch to be able to close, thennode 108G would go to step 640 and execute the synchronization and errorcheck routine. If an error is detected during this time then at step 642it is recorded and the transfer is stopped. Otherwise, at step 652 acheck is made to see if this is the first iteration of the loop. If itis the first iteration the local record is transmitted to the nearestneighbors at step 653. If it is not the first iteration then the processcontinues at step 638 to determine whether the normally open switch canbe closed.

If the normally open switch is unable to close at step 640 (as above)and transmits its local record to its nearest neighbors, node 108D willreceive the notification and enter the transfer process state at step610. Node 108D will continue through the transfer process (steps 612,616, 618 as stated elsewhere) and since it is on the unaffected portionof the circuit it will pass through step 644 and into step 645.

In the illustrative embodiment, steps 645-651 provide notification andenable nodes that were otherwise unaffected by the transfer event toadjust their protection settings to pick up additional load during thetransfer process. It would not deviate from the scope of this inventionfor the adjustments to include other settings or operations related toswitched capacitor banks, voltage regulators or other devices.

If node 108D is the last member of the team (only one neighbor exists),it will calculate the segment count allowed in step 647 and transmit itslocal record, including new segment count, to its neighbor in step 649.Then, node 108D will enter step 632 where it will wait for the transferprocess to end, along with checking for errors in step 634.

If node 108D is not the last member of the team (it has two neighbors),it will enter step 646 to transmit its local record to its nearestneighbors. Before it can continue through the transfer process, it mustreceive a notification back from node 108E with 108E indicating it hasprogressed into step 632 (node 108E has entered the transfer process andfollowed the same process as node 108D). Until that indication isreceived, node 108D will cycle through the error detection step 650.Once the data is received, node 108D can continue to step 647 tocalculate a new segment number, step 649 to transmit its local record toits neighbors, and to the step 632 and step 634, looping until thetransfer process is complete.

Node 108G will receive the updated local record from node 108D when node108D has passed through step 649 and into step 632. Node 108G can nowuse this updated record to determine if it can close in step 638. Ifnode 108G is still not allowed to close it will continue with the errordetection loop which includes step 640. If node 108G is allowed toclose, it will continue to step 626 to close its switch.

Otherwise, the node will continue to cycle between steps 638, 640 and650 until the switch can be closed, an error is detected, or the endtransfer process timer expires. It should be noted that in the case ofteams containing only sectionalizing switches without protectivecapabilities, the number of segments criteria will always be satisfiedwithout additional communication, and the only typical condition thatwould delay closing of the switch would be a wait for the other affectednodes to reach the correct transfer process state. This distinctionallows the support for profile modification in protective devices to beadded to prior reconfiguration products in a compatible manner.

Once node 108G determines that it can close, its associated switch itwill proceed to step 626 and attempt to close it. Typically, suchswitches will have safety devices called lockout logic, as detailedabove during the discussion of sectionalization, that will force theswitch back open and keep it open if an anomaly such as a voltage lossis detected when the switch is closed. At step 628, the switchdetermines if the closing operation was successful. If it was not thenat step 624 an error flag is set and the transfer process is stopped. Ifthe close operation was successful, then power is restored to users 104Cand node 108G continues to step 630. At step 630, node 108G sends itsupdated record to its nearest neighbors, nodes 108C and 108D. Node 108Dnow enters the transfer process state, and as nodes 108A, 108B, and 108Cdid, node 108D will proceed down the flow chart to step 618 and send itsupdated record to nodes 108G and 108E. This will cause node 108E toenter the transfer process state and signal nodes 108D and 108F causing108F to enter the transfer process state and signal node 108E with itsupdated recorded.

As can be seen from the present example, one feature of the invention isthat from only the ordering of the nodes in the database and the rulesof the flow charts, each node can determine the appropriate actions totake independently of actions taken by other nodes. Nodes do not commandother nodes to take any given action, nor is central control or humanintervention necessary to coordinate the response of the entire system.The decisions made by each node are based solely on information it hasstored in its database and sensors attached to it.

Nodes 108A, 108B, 108C, 108D, 108E, and 108F all will proceed to step644. Since the switches at nodes 108D, 108E, 108F are normally closedswitches and they were not affected by the fault, they will be sent tostep 632 at step 644 and will wait for the process to time out whilethey perform the synchronization and error checking loop with steps 634and 636.

Since the switches at nodes 108A, 108B, and 108C were affected by theevent, they each proceed to step 620. In the illustrative embodiment ofthe invention, the conditions listed in Table 3 are checked by the nodein order to determine if it can reclose. The conditions used at step 4in Table 3 are shown in Table 2. Other sets of conditions could be usedwithout departing from the invention.

If these switches cannot be reclosed, then, the nodes will go to step622 and perform synchronization and error checking. In the illustrativeembodiment if an error is detected, then in step 624 a flag will be set,and the transfer process state will be stopped. It will be appreciatedthat in other implementations of the invention error flags may causedifferent results. In one example, error flags may be prioritized sothat lower priority errors may not stop the transfer process.

If no error was detected at step 622, at step 654 the number of segmentsthat can be picked up is recalculated using the rules for calculatingthe number of segments field during transfer events. If the result ofthis recalculation may allow the normally closed switch to reclose, atstep 620 the logic will exit from the loop and reclose the switch atstep 626. Otherwise, each node will cycle through steps 620, 622 and 654until the switch can be reclosed or the process timer expires.

Table 3

In order to reclose the normally closed switch associated with a node,one valid closed switch and one valid open switch must be detected asthe adjacent switches associated with adjacent nodes on either side ofthe normally closed switch. The following rules define the conditionsthat must be met for the normally closed switch to validate the state ofadjacent switches.

A presently open switch on the load side of a faulted line section mayclose for the purpose of restoring load if:

-   1. no error conditions exist-   2. the adjacent fault side switch is open-   3. the adjacent fault side switch did not detect a fault, but did    see a loss of voltage-   4. the current level seen by the adjacent fault side switch before    the outage is within the bounds set in the local switch (The    conditions used in this step are shown in Table 2.)-   5. the adjacent non-faulted side switch indicates it observed a    voltage loss and/or fault but it is now closed, or the adjacent    non-faulted side switch is the normally open switch, or the adjacent    non-faulted side switch is a breaker and voltage has been restored-   6. the “number of segments” that can be picked up is greater than    zero. For this test, the number from the local record of the team    database corresponding to the non-faulted direction of supply (left    or right) is used.-   7. the adjacent switches are in the proper logical operation step

A normally closed switch on the source side of a faulted line sectionmay reclose if:

-   a. no error conditions exist-   b. the adjacent fault side switch is open-   c. the adjacent fault side switch detected a fault-   d. the adjacent non-faulted side switch indicates it saw a voltage    loss and/or fault but it is now closed, or the non-faulted side is    the breaker and voltage has been restored-   e. the adjacent switches are in the proper logical operation step

Through the use of algorithm of Tables 2 and 3, a node can determine onits own whether or not it can close its associated switch. Assume thatall of the conditions are met to allow the switch at node 108C to beable to reclose its switch. The switch will then be reclosed at step626.

At step 628, node 108C will determine if the switch was successfullyreclosed. If it was not, then an error flag is set and the transferprocess is stopped in step 624. If the switch was successfully reclosed,then the node proceeds to step 630 and informs its nearest neighbors,nodes 108B and 108G, of its progress by sending them an updated versionof its record. Node 108C then enters the loop between steps 632 and 634where it performs the synchronization and error checking routine whileit waits for the end transfer process timer to time out. If an error isdetected, step 636 is executed and a flag is set and the transferprocess is stopped. An example of an error is if the lockout logiccauses a switch to reopen.

As the above discussion and rules indicate, one benefit of the presentinvention is its ability to operate by systematically closing only oneswitch at a time so that the load to the system is brought on linegradually, one segment at a time. This helps ensure that the powersource will not be overloaded due to too rapid an increase in demand.

When node 108B receives the communication from node 108C, assume thatnode 108B will have enough information to know that according to theconditions listed in Table 3, it should not close since node 108Adetected a fault and node 108B did not. This must mean that the faultwas between nodes 108A and 108B. Therefore, node 108B will cycle betweenstates 620 and 622 until an error is detected or the end transferprocess timer expires. Node 108A, since it has detected a fault, willalso not be allowed to close and will cycle though steps 620 and 622until an error is detected or the process timer times out.

When the end transfer process task timer times out, the nodes will allreturn to step 310 of FIG. 3 and resume synchronization, error andintegrity checks until the original fault is repaired. If the fault isrepaired, the system will enter the return to normal process state ofFIG. 7 discussed below. If another fault occurs before the previous onehas been corrected, it would not deviate from the present invention forthe system to re-enter the transfer process state and again recloseswitches to return service to as many users as possible.

Return to Normal Process State

After a fault has occurred or if for any other reason the distributionnetwork switches have been put in states other than their normaloperating states, for example after the transfer process has completed,the return to normal process state can return the system to its normaloperating configuration. This process can also be used to reconfigurethe distribution system to any desired system set up of open and closedswitches without deviating from the present invention. In the exampleused above, once the fault in distribution line 106 has been repaired orcleared and switch 108A has been manually reclosed, power will berestored to users 104A. At this point, node 108B will sense that normalvoltage has been restored to the distribution line between nodes 108Aand 108B and it will be triggered to enter the return to normal processstate after node 108B has detected stable 3 phase voltage on the channelfor a predetermined time and no errors exist and the normally openswitch has not detected a fault. Once any switch in the system hasentered the return to normal state, it will signal all other switches toenter the return to normal state.

In the illustrative embodiment of the invention, a node without voltagesensors on the normal source side of the switch may use information fromthe nearest source side neighbor to determine if voltage has beenrestored. To do this, the node assumes that voltage has been restored ifthe nearest source side neighbor node has a closed switch and isdetecting good voltage. The local node must see this condition continuefor a predetermined time to validate that voltage has returned.

In another embodiment of the invention, the return to normal process canbe triggered on demand by an external device or human. It will beappreciated that this on demand activation of return to normal can beused for, but not limited to, starting the return to normal processbefore the predetermined time has elapsed, or as a one step method ofreturn to normal without manually closing any team switches.

The return to normal process can occur in one of two methods, an opentransition or a closed transition. As is well known by those skilled inthe art, an open transition is one in which the source of supply ofpower to users is interrupted in the process of switching betweenalternate sources of supply. For instance, in this example, if tieswitch 108G was opened up before switch 108B was closed then users 104Band 104C would momentarily lose power. This would be an open transition.In a closed transition, switch 108B is closed before switch 108G isopened and users 104B and 104C do not lose power. The system operatorcan configure the system to operate in either an open or closedtransition mode.

During a closed transition, the normally open device must reopenfollowing the allowed transfer time whether it has heard from thenormally closed but presently open device or not. This is done toprevent the parallel of lines for an extended period of time. Also, ifthe node with the normally open switch detects that a parallel conditionexists before the return to normal process has begun, the node willbegin the return to normal process and open its switch to break theparallel.

It is well known by those skilled in the art that the reliability of theclosed transition return-to-normal sequence is greatly facilitated ifthe automated logic can adjust the settings of the protective devices onthe circuit just before and just after executing the closed transition.These adjustments include but are not limited to blocking and unblockingthe ground fault detection on nodes that act as protective devices.Thus, it is an object of the present invention to provide the means tocoordinate these adjustments with the closed, return-to-normaltransition, as outlined below.

At step 712, the node starts the end transfer process task timer. Eachnode will use the same start time for its end transfer process timer.This timer ensures that the system does not spend too much timeattempting to execute the return to normal process. The timer is set torun for a predetermined time set by the system operator. In oneembodiment, this timer is set to run for one minute. The node nextexecutes step 716. Since nodes 108A-F are normally closed switches, eachof these nodes continues on to step 718.

Switches 108D-F are normally closed switches that were not open so theywill each go to step 750, where if the transition method is closed thenodes will continue to step 751 to perform actions that will preparethem for the closed transition. The nodes then continue to step 730 andperform a synchronization and error checking loop while they wait forthe process to end. If the transition method is open, the node willsimply progress from step 750 to step 730 to perform the synchronizationand error-checking loop.

Switches 108A and 108C are normally closed switches that were reclosedby the transfer process so each of these nodes will also go to step 750,where if the transition method is closed the nodes will continue to step751 to perform actions that will prepare them for the closed transition(as stated previously). The nodes then continues to step 730 andperforms a synchronization and error checking loop while they wait forthe process to end. If the transition method is open the nodes willsimply progress from step 750 to step 730 to perform the synchronizationand error checking loop.

Node 108B is a normally closed switch that is open so it moves on tostep 720 to determine if it is an open transition.

Assume the system operator set the system to undergo a closedtransition. Then, node 108B goes from step 720 to step 752 to performactions that will prepare it for the closed transition (as statedpreviously), then to step 722. If the normally open switch, 108G, isarmed to reopen (see below), the switch on the supply side of switch108B, switch 108A, is closed, and communication of the initial startreturn to normal process message was successful to all members of theteam, then node 108B will continue on to step 724 and close its switch.The requirement of the reply to the initial start return to normalprocess message insures that all nodes within the team have preparedthemselves for the closed transition state. The normally open switch isarmed to reopen when it has entered the return to normal process, themethod used will be a closed transition, and it has informed all othernodes in the team of its state, as will be seen in greater detail below.

If the normally open switch is not armed, or the supply side switch isnot closed, or the initial start return to normal process message hasnot yet been successfully sent to all team members, then node 108B willperform a synchronization and error-checking loop and return to step722. This loop will continue until either all conditions are met or theend transfer process timer expires.

If the switch is closed at step 724, then at step 726 the node checks tosee if the switch is closed. The switch could have been reopened bylockout logic or any other safety feature on the switch that might forceit back open. If the switch is closed then at step 728, the node willinform its nearest neighbors and the normally open switch, 108G, bysending them an updated version of its record. The node then goes tostep 730 where it performs the synchronization and error checking loopwhile waiting for the end transfer process timer to time out. If theswitch is not closed at step 726, then at step 732 an error flag is setand at step 734 the node informs all other nodes that an error hasoccurred and the node then goes on to step 730.

If the system is set to undergo an open transition, then at step 720,the node will go to step 746. If the normally open switch is open andthe supply side switch, switch 108A, is closed then the node willcontinue on to step 724. If either of these conditions is not met, thenthe node will perform a synchronization and error-checking loop betweensteps 744 and 746.

Switch 108G is a normally open switch so at step 716 it will proceed tostep 736. If the system is undergoing a closed transition, the node goesto step 753 to perform actions that will prepare it for the closedtransition (as stated previously), then to step 754 where it will armitself to open and send its local database record to all other teammembers, and then to step 738 where if all the other switches areclosed, node 108G will open the normally open switch at step 740. Thenode will then check if the switch is actually open at step 742. If theswitch is open it will send its updated record to all the nodes at step734 and then enter the loop at step 730 and wait for the process timerto end. If the switch is not open at step 742 then an error flag will berecorded at step 732 and the node will proceed to step 734.

At step 738, if all the other switches were not closed, then the nodewill loop to step 744 and perform synchronization and error checking andlook back to step 738. This loop continues until all the switches areclosed, an error is recorded or the timer expires.

If the system were programmed to undergo an open transition, then atstep 736 node 108G would not look to see if other switches were closedand it would skip to step 740, open the switch and continue the flowchart from that step.

End Process Timer Task

Whenever a node enters either the transfer process or the return tonormal process, the node starts the end process timer task. The flowdiagram for this task is show in FIG. 8. At step 812 the node loopsuntil the timer expires. The timer is initiated when the node enters thetask and from the information sent to the node by other nodes, each nodewill know the time at which the first node to enter the task in questionbegan the task. In this way, all of the nodes can set their end processtimers to expire at the same time. It would not deviate from theinvention to have the end process task timer be of different durationsfor the transfer process and the return to normal process.

Once the timer expires, the node will stop the process it is in at step814. At step 830, if the process that was stopped was a closedtransition return to normal event, the node will continue to step 831 toreturn settings that were changed to prepare for the closed transition(for example unblocking the ground relay if applicable). It should beappreciated by those skilled in the art that the reset of the closedtransition settings could also be accomplished after step 734 or at anytime when the normally open switch has been verified to be successfullyreopened. From both step 830 and 831, the node will continue to step 816and look to see if the switch is in the proper position for the end ofthe process that was stopped. For example, is the switch in its normalposition at the end of the return to normal state. If the switch is notin the correct position, then step 818 is executed and an error flag isset and the node returns to the synchronization process at step 820.

If the node's switch is in the correct position then at step 816, thenode goes to step 822 and checks to see if the circuit is in the normalconfiguration. If it is, then the node goes to step 820. If it is not inthe normal configuration, then the node goes to step 824 and checks ifthe return to normal is enabled. If the system does not have the returnto normal enabled it will go to step 826 and change its operation stateto no operation and wait for further instructions before it can re-enterthe ready to transfer state. From step 826, the system will go to 820.

If the return to normal is enabled then at step 828, the node changesits operation state to ready for return to normal and then proceeds onto step 820.

Sideline Team Nodes

As will become apparent to those skilled in the art, the use of thesideline team node in accordance with the present invention expands thecapability of the method and apparatus to operation of more complexcircuit topologies and more diverse sources of data.

The sideline team node may be distinguished from active team nodesmentioned previously in two ways; 1) the sideline team node is notactive within the synchronization and integrity check process, 2) thesideline team node does not itself directly execute a process associatedwith the reconfiguration process described previously. Instead, thesideline team node is used by an active team node to acquire additionaldata about the environment around the team. This data can then be usedto alter the process within the team. This will become clear with theuse of two examples below.

It will be recognized by those skilled in the art that the method foracquiring the additional data will usually involve data communications.This may be achieved using various communications technologies forpoint-to-point communications or may be achieved by sharing the samecommunication infrastructure used by the team communication channel,110. In addition, in the case of dual or multiple switch nodes, thecommunication step may be bypassed entirely.

In the illustrative embodiment of the present invention, each activeteam node may be responsible for one sideline team node. The addressingof sideline team nodes is contained within a table similar to thedatabase of node records. The address data for the sideline team node iscontained in the record with the same device number as the record in thedatabase of node records for the active team node that is responsiblefor the sideline node. Other means for storing sideline team nodeaddressing is also possible without deviating from the intent of thepresent invention. For example, it would also be consistent with thepresent invention for the table storing sideline node information toinclude identifiers that would specifically associate a sideline teamnode with an active team node, thereby allowing the number of sidelineteam members per active team node to be greater than one.

With reference now to FIGS. 9 and 10, the following are two examples ofuses of the sideline team node. Those skilled in the art will recognizethat S1-3, (901, 902, 904, 1001, 1002) are all sources of supply for thecircuits. Nodes 903A, 903C, 1003A, 1003C, 1003D and 1003E are allnormally closed switches. Nodes 903B, 903D and 1008B are all normallyopen switches. It will be obvious to those skilled in the art that thesesimple examples were chosen for the purpose of illustrating the possibleuses of sideline team nodes, and that much more complex applications arepossible. For example, it would be consistent with the present inventionto utilize sideline team node communications to allow multiple teams tointeract in order to reconfigure circuits with more than two possiblesources.

The data available from the sideline team members could also be morecomplex. This data could include protection data such as present loadreadings, maximum available load current, etc. to prevent animpermissible amount of load to be picked up, power quality data such asvoltage or harmonic content that could also be used to block transfer ifit would negatively impact customers on the alternate source, or otherdevice-specific data such as abnormal conditions in the sideline nodecontroller.

The first example refers to sideline node 903C and team nodes 903A and903B in FIG. 9. Team node 903B is responsible for collecting data fromsideline node 903C, and using that data to make decisions about theoperation of the team. In this example, the circuit containing teamnodes 903A and 903B is normally fed from source 901, and uses themid-point of circuit fed from source 902 as its alternate source suchthat if 903A were to be opened by a reconfiguration event, and 903Bclosed, the load served between nodes 903A and 903B would be fed fromthe alternate source 902.

It is important to note for the purpose of this example that source 904is not capable of handling the additional load between 903A and 903B ifnode 903D were closed and 903C were open, and a reconfiguration eventwere to occur. For this reason the data that 903B retrieves from 903C isused to determine the alternate source that is presently available. If903B finds that 903C is closed, source 902 must be the present alternatesource, therefore, the load between 903A and 903B could be transferredto the alternate source if necessary. If 903B finds that 903C is open,source 904 would be the present alternate source, therefore areconfiguration event can not be allowed.

This logic is illustrated in the flow diagram in FIG. 9. The steps inthis flow diagram are executed in parallel to, but not connected with,the synchronization and integrity check process running in node 903B. Itis assumed that upon start of the node's logic execution that a sidelinenode has been configured into the sideline table in node 903B. Node 903Bbegins polling the sideline node at step 921. With the data retrievednode 903B checks whether the sideline node is closed at step 922. If thesideline node is not closed, or the closed status of 903C cannot bepositively verified for any reason, the logic proceeds to step 923 toset a flag to prevent automatic circuit reconfiguration from occurring.It will be appreciated by those skilled in the art that the pollingloop, 921-926 could be replaced by a spontaneous report by exceptionscheme or other means to acquire the state of 903C, subject to therestriction that the data must be acquired and validated within a periodof time comparable to the configurable polling delay referred to at 926.

If in step 922 it is found that the sideline node is closed, node 903Bcontinues to step 924 where if the flag to prevent reconfigurations isset, it can be cleared in step 925, otherwise no further action isrequired. In all cases, node 903B will go to step 926 to wait apreconfigured amount of time before going back to step 921 to begin thepolling cycle again.

It will be appreciated by those skilled in the art that if nodes 903Cand 903D were themselves a switch team, node 903B could be used as asideline node off of either node 903C or node 903D. In this way each ofthe two teams could prevent the other team from automaticallyreconfiguring its circuit if either team was already in a reconfiguredstate. It can also be appreciated that as teams grow in nodes, many moreinterconnection possibilities arise, each being consistent with thepresent invention.

The second example refers to FIG. 10 with nodes 1003A, 1003B, 1003C and1003D comprising a switch team being fed from sources 1001 and 1002.Additionally, node 1003E is a sideline node (a simple, SCADA operableswitch with fault detectors) installed on a tap line that feeds to adead-end. Sideline node 1003E is contained in the sideline table of node1003D such that node 1003D is responsible for retrieving data from node1003E and using the data to enhance team operation.

In the present example, the settings of the breaker at source 1002 areconfigured such that the breaker will go to lockout on the thirdoperation. It is also desirable to prevent any switches from opening onthe first operation of the breaker to allow temporary faults to clear.This implies that nodes 1003C and 1003D must open their switches afterthe second operation in order for the fault to be cleared, areconfiguration to begin, and as much of the load to be picked up aspossible.

If a permanent fault were to occur on the line between 1003E and the endof the line, source breaker 1002 would operate twice, after which nodes1003C and 1003D would open to begin the reconfiguration process. Asdescribed earlier, node 1003B would close into open node 1003C, thebreaker would close into open node 1003D, leaving the fault apparentlyisolated between nodes 1003C and 1003D.

In this example, the execution of the logic associated with the sidelinenode is performed after the transfer event has completed. After thetransfer event, node 1003D will poll sideline node 1003E for data. Thisdata will include the indication of a fault past sideline node 1003E.Knowing the normal configuration of the circuit, and the more specificlocation of the fault, node 1003D can further isolate the fault bysending a command to sideline node 1003E to open its switch. Uponverification that the sideline node's switch is open, node 1003D canautomatically begin the return to normal process, restoring load to thecustomers bordered by the three nodes 1003C, 1003D and the now open node1003E.

This logic is illustrated in the flow diagram in FIG. 10. As statedpreviously, the logic is only executed following the end of areconfiguration event, and before a return to normal event. After thereconfiguration event the node enters the logic and polls the sidelinenode at step 1021. If the data retrieved indicates that no fault wasdetected by the sideline node at step 1022, or any other abnormalcondition is detected such that the location of the fault cannot beverified to be on the load side of 1003E, the node proceeds to 1023 toend the logic. If a fault was detected at step 1022, the node thendetermines if the sideline node is presently open in step 1024. If thesideline node is not presently open, the node continues to step 1025 towhere it sends an open command to the sideline node. The node then againchecks if the sideline node is open in step 1026 and if not can stop thelogic at step 1027, or optionally retry the open command. If thesideline node is now open at step 1026, it will continue to step 1028where it will signal the return to normal logic to begin. If the nodewere to find the sideline node 1003E initially open at step 1024, itwould immediately continue to step 1028 to signal the return to normallogic. In both cases, this logic ends at step 1029 after the return tonormal logic has been signaled.

It can be seen by those skilled in the art that numerous other possiblecircuit configurations are possible using this form of sideline nodelogic while remaining consistent with the present invention. Neither thenumber of nodes in a team nor the complexity of the circuit affect theuse of this logic. For example, it will be appreciated that node 1003Ecan be associated with an automatic sectionalizer, contained in anotherteam, or backed up by an alternate source without deviating from thepresent invention.

Protective Device Add-On Board

In the illustrative embodiment of the present invention, the methoddisclosed above is incorporated into the operating instructions orstored program of the team node controller 200. Alternate embodiments inthe form of microprocessor-based add-on boards support retrofit ofproducts configured according to existing, prepackaged line reclosercontrols and substation breakers.

A block diagram of the recloser version of the add-on board is shown inFIG. 11. The board consists of a small electronic microprocessor-basedcircuit board, which can be provided for mounting inside an existingrecloser control cabinet, or in a nearby auxiliary cabinet. The powerfor the board is supplied by the recloser's power supply/battery backupsystem 1104. The team reconfiguration logic is entirely contained in thememory 1105 and CPU 1106 of the add-on board, while the circuitprotection logic and active switching functions remain in the reclosercontrol. Thus, the addition of the team reconfiguration logic disclosedherein can be performed without modification to the logic orfunctionality of the recloser. The interface between the add-on boardand the recloser is based entirely on digital communications. It iswell-known to those skilled in the art that many of the modern,microprocessor-based recloser controls (including those mentioned in thebackground section) support well-defined digital communicationsprotocols such at DNP 3.0 and Pacific Gas and Electric Protocol in sucha way as to allow the recloser functions to be selected, controlled andmonitored over a communication port. This port is provided as part ofthe recloser control. The specific data values, status points, andcontrol outputs that can be exchanged over communications are typicallyprovided as predefined “points lists” by the designer or provider of therecloser.

In light of the functionality provided by the recloser and itscommunication interface, the functions of node controller of FIG. 2 canbe partitioned between the add-on board and the retrofit reclosercontrol as follows: The team communication functions 110, 218, 220 areprovided by one or two of the communication channels 1101 and 1102 onthe add-on board. The third channel, 1103 is used to communicate withthe recloser. The team coordination logic performed by 208 and 210including maintenance of the team database 210 is performed by theprocessor 1106 and memory 1105 of the add-on board. The node's userinterface for team functions 209 remains with the add-on board 1107,while the recloser's user interface can still be used for accessing itsstandard functions. All of the recloser protection features includingovercurrent fault detection 212, switch monitoring and control 216 areutilized, with the add-on board receiving status from all of thesefeatures over communications. Supervisory control over the recloser'sassociated switch (breaker) is provided to the add-on board via thecommunication protocol. Power management and battery backup 1104 must beprovided separately for the additional add-on board/communicationequipment, although this may in some circumstances be shared with therecloser's power supply 222.

In circumstances where the team logic requires interaction with datastored or processed in the recloser, the recloser point list isutilized. The presence of overcurrent faults, line voltage and othersensed or derived parameters are all readily obtainable in this manner.For example, load data required to support load pickup at steps 620 and638 can be periodically sampled by the recloser, transferred to theadd-on board using the point list and averaged inside the add-on board.

An additional benefit of the add-on board is its ability to extend thecapabilities of the recloser's basic functions. For example, the CooperForm 4C recloser supports only two protection profiles. Because of theadditional storage and processing capabilities of the add-on board,additional profiles can be stored in the add-on board and loaded intothe recloser when needed. In addition, the extensions to therepresentations of protection profiles presented in this invention canbe applied uniformly to all retrofit reclosers without regard to thecapabilities of the individual device.

Yet another embodiment of the add-on board is provided by including theoptional analog and digital I/O block 1108. This embodiment could beutilized for interfacing to a substation breaker lacking an adequatedigital communication capability to support the team functions. Thedigital I/O would then be connected to the breaker's status and overridecontrol points. The analog I/O would be connected to current and voltagesensing devices to allow the node to provide the load and voltagemonitoring functions of a team member. The breaker's protection profilewould be dictated by the breaker's independent settings and configuredinto the memory 1105 of the add-on board. Those skilled in the art willrecognize that many possibilities exist for supporting teamfunctionality in legacy or retrofit devices.

Multiple-Team System

Considering now additional aspects and features of the presentinvention, FIGS. 12-14 illustrate the overall logical organization andthe data structure wherein more efficient and flexible response toabnormalities is provided to reconfigure and restore service to endcustomers (circuit reconfiguration); i.e. to enhance thereconfigurability of the distribution system especially in largerdistribution systems. For example, in one arrangement of the invention,“teams” of nodes or team members are defined in the distribution systemhaving associated switching controls with the various teamscommunicating amongst each other to “negotiate” or work out the mostefficient and expeditious reconfiguration of the system in response to afault conditions and other circuit abnormalities.

FIG. 12 illustrates a representation of the overall logic of a singleteam member. In an illustrative example, the Sectionalizing logic blockin the Switch and Sectionalizer box is the same as described earlier inconnection with the embodiment of FIGS. 1-8 and in U.S. Pat. No.6,018,449 and based on EnergyLine Model 2801 or 2801-SC. FIG. 13illustrates the data structure for the overall system. FIG. 14represents an illustrative representation of the overall logic flow toaccomplish the basic functions of the invention at a single team memberlocation as shown in FIG. 12 based on the system data that is obtainedas will be explained in more detail hereinafter. With additionalreference to FIG. 15, the distribution system is organized or defined byfields, e.g. Field B including Team members Switches 6, 7 8 and 9 andField C including Switches 8 and 23 such that team member Switch 8 is amember of both Fields B and C.

In the illustrative embodiment, resources are provided for each fieldthat move between or visit each team member and cooperate and coordinateoperation and system response of the team members. For example, theresources may be referred to as a “Coach” or “Agent” for each field, theterm Coach being utilized hereafter for simplicity but not to beinterpreted in any limiting sense. Further, the team members may also bereferred to as “players” on the team.

In a particular arrangement, decisions on how to respond to particularsystem conditions is achieved via a negotiated plan between teams andteam members, i.e. an agreement between the coaches of the teams. In apreferred embodiment, the communicated information includes not onlydata on adjacent team members and data from other external teamsrepresenting system information, but also includes task identifiers andfunctional representations on how to respond to particular systemconditions as sensed and in accordance with a plan of response per“negotiations” amongst teams. The task identifiers and functionalrepresentations may also be characterized as instructions, responses andimplementation rules. Thus, the present invention provides coordination,flexibility and efficiency to restore service to the largest percentageof the system.

Defintions useful to explain the illustrative examples are as follows:

-   -   Field—A portion of a distribution system bounded by automated        switch locations.    -   Team—The automated switch locations associated with a Field.    -   Coach—resources having similarities to a software agent        responsible for maintaining service to a Field by using the Team        members at its disposal.    -   Loop Teams—Any team with two sources, each directly from a        substation.    -   Radial Teams—Any team with no more than one source.    -   Floating Teams—A team where no sources are directly from a        substation. Instead the sources are from mid-circuit tie points.    -   Hanging Loop Team—A team which has one substation source, and        one mid-circuit source.    -   Hanging Radial Team—A radial team where its one source is a        mid-circuit source.

The “primary mission” (function) of a Coach is to keep service to itsrespective (his being used hereafter for simplicity) Field, and will doso using information from his Field and from Coaches on adjacent Fields.A secondary mission of the Coach is to restore a Field back to itsnormal state, and will do so immediately if that option exists. If thenormal source is not available, the Coach will look to alternate sourcesas a temporary means to restore service to his Field. In addition, aCoach cannot act by himself. To insure coordination and structure aCoach must consult with the Coach from the adjacent Field, and they mustagree on the course of action. The Coach can be characterized in variousways for understanding and illustrative purposes, e.g. 1) a resourcewhich is communicated or moves around and visits team members to controland coordinate tasks; 2) a token that gives a Switch Control the powerto make decisions, provided the Switch Control has all the necessarytokens.

Considering now additional aspects and features of the presentinvention, in order to best describe and understand illustrativeexamples and not to be interpreted in any limiting sense, a listing ofgeneral rules, attributes and data that could be established to suitablycontrol a system and practice the present invention are as followes:

Fields link to other Fields at Team member locations. Any single Teammember will be part of one or more Fields, and so will be visited by oneor more Coaches. A Field must contain at least two Team members. Asubstation breaker can be one of those Team members, provided that aninterface module exists at the breaker. Information will be passedbetween Fields using the Team members as semaphores. In this way thestatus of any single Field can be propagated throughout the associatedpart of the distribution system.

The rules for restoring service are very similar to the rules that existin the prior IntelliTEAM product as discussed hereinbefore. The presenceor absence of voltage and fault current on adjacent line sections willremain as the key to service restoration. Previous rules forcoordination of logic (process step counter) will be replaced by similarrules related to the Coach process. A Coach will carry the necessarystate machine information, and along with the state machine informationfrom an adjacent Coach, coordination will be guaranteed.

Time synchronization over a wide area will be replaced by individualactivity timers. A Coach needing additional information from an adjacentField will allow the adjacent Coach a limited time to retrieve thatinformation. If the timer expires, the first Coach has the option tofind another solution at another Team member. By keeping statistics onthe restoration performance at each Team member a Coach can dynamicallyprioritize the strategy for restoration of the Field.

The Coach will be required to visit each team member on a predeterminedtime interval. During quiescent periods this means the Coach will travelbetween Team members on some regular interval (maybe 3 minutes). If aTeam member does not hear from the Coach in this period of time, theTeam member will flag an error condition. Each Team member will have aseparate timer associated with it that will be updated with any visit.Due to the lack of a common clock, the coach will try to visit everyteam member in half the configured time. This should handle thepotential communications propagation delay (which will be assumed to bezero).

Each Team member will also be able to call out to the Coach, and allother Team members on the Field, when a local event occurs that willaffect the Field. For example, manually placing a Switch Control inDisable Automatic mode will initiate a message to the other Teammembers. This will cause the Coach to also learn of this change instatus, and use this new information when other events occur. All eventscategorized as critical will be immediately propagated in this way.

Attributes of the Field

-   -   Number of switches    -   Priority of load    -   Present source switch    -   List of alternate sources switch to try (optional configuration)    -   Maximum number of additional fields that can be added to circuit    -   Enable/disable of Contract method that arbitrates the addition        of fields    -   Enable/disable automatic operation    -   Return to Normal time setpoint in minutes    -   Indicator—field is operational    -   Present average 3-phase load for this field    -   Available local capacity=max team cap−extended load    -   Capacity for line section and its downstream loads    -   Lesser of Max rated team capacity and team avail capacity    -   Visit Timer used by local team member    -   Field Configuration error code    -   Flags to indicate OC/VL status of field    -   Extended Loading of field (this and downstream fields)    -   Switch record with the vaild active RTN timer    -   Switch record for return trip for traveling coach    -   Transfer or RTN state    -   Coach ID    -   Coach visit counter    -   Coach present (yes/no)    -   Flags set by other processes to indicate the coach was here    -   Setup data for this field

Team Members

Attributes of Team Members

-   -   1. Normal switch state    -   2. Normal field association (closed source, tie, etc)    -   3. Return to normal mode (open, closed, none)    -   4. Location of normal source side sensors    -   5. DNP RTU address    -   6. Switch position number (0 . . . 7)    -   7. Maximum current this switch can handle in season 1    -   8. Maximum current this switch can handle in season 2    -   9. Current switch state (e.g. 0=unknown, 1=closed, 2=open)    -   10. Event status bitmask    -   11. Reverse current indication    -   12. Mode bitmask (e.g. 0—unknown, 1=man, 2=auto, 4=lov)    -   13. Total Average load    -   14. Countdown timer for next required visit by coach    -   15. Last saved event sequence number for this switch    -   16. Number of line segments sourced from this switch

Coaches—contains necessary and desirable data to perform the tasks. TheCoach carries a set of task identifiers along with the data. These taskidentifiers will cause specific logic paths to run in the switch controlwhen the Coach arrives as discussed further in connection with FIG. 22.Both the task identifiers and the data will change as the Coach travelsfrom team member to team member.

A Coach has a coach ID number and an incrementing visit counter.Normally the coach roams the field at will. He must visit every teammember in a prescribed period of time though. If he arrives at a teammember that has already received that ID and visit counter (the countermust be greater than the last if the ID is the same), the coach assumeshe is a duplicate and dies. If the coach arrives to find another coachwith a higher ID has visited, again, this coach dies. If a team memberdoesn't hear from the coach within a prescribed period (2× the visittime), that team member can spawn a new coach with an ID number onehigher than the last coach he heard from, and a new visit counter. Thenew coach must determine the state of the field and begin to take actionif necessary.

The Coach will carry task identifiers (numbers) that a task manager willperform. The tasks that need to be performed at each team member willchange as the conditions change in the field. There is a linked list ofcoach buffers in each team member. Each coach includes a list of activetasks that he is working on. At each team member he will evaluate thelist of tasks, perform any action possible, and add or remove tasks asnecessary. In the preferred embodiment, the software facilities for thecoach function, e.g. coach logic executable code, will reside at eachteam member.

The task list will contain records that consist of a task number, thecoach that owns it, and a priority of the task.

Tasks have attributes which include the Coach ID, Task Owner (the teammember where the task was originated), a Task Sequence (unique ID #),and a Time-to-Run attribute. As a comparison with the embodiment ofFIGS. 1-9 where it might be stated that the switch control performsspecific logic until it is given adequate data to move on, in theillustrative embodiment, the data sent to a team member will causespecific logic to run while the coach is present to supervise.

Rules for Team Availability

The evaluation of team readiness can be broken down into the followingfour categories.

The user may enable or disable funcationlity on a per-team basis. Thesetup parameter will be available as a SETUP function of TeamConfiguration, once for each team on each team setup. The parameter mustbe a global parameter so that it is set the same in all members of theteam. The term global is used herein to mean overall controlled system.The coach will be responsible for verifying that all team members on thefield contain the same status, and will issue an error if they do not.

In order for any one switch to be used in a transfer process, both teamsin the adjacent fields must be enabled. However, if one team is enabledand one is disabled, only the one common switch will be affected in theenabled team. Other team members in the enabled team will be allowed tooperate if their conditions allow it.

Field Enable/Disable

When changing the team configuration due to permenant circuitmodifications, it is beneficial to stop the team communications. Thisconsists of stopping the coach from visiting team members, and stoppingevent messages from being generated. To do this a Field Enable/Disableparameter will be available on the SETUP: Team Configuration screens,once for each field/team on each of the eight team screens. To disablethe entire field/team, the user will need to manually set this parameterto disabled at each team member.

Team Member Operational

A team member (switch) will be operational if the following are true:

-   -   1. the switch has automatic sectionalizing enabled    -   2. human intervention has not changed the state of the switch    -   3. TEAM process enabled by the user    -   4. the field is operational    -   5. there are no significant errors present

Team Ready to Transfer Indication

The Ready to Transfer indication is primarily a user interface issue. Ateam will be Ready when all team members are Operational. The Ready toTransfer indication displayed at any one team member will not exactlyfollow the true ready state of the team. It will be delayed intransition between on and off for the amount of time it takes the coachto return to the team member.

The operational status of the team members will be indicated by thestate of the TEAM mode bit in the automatic operation byte the coachcarries for each switch.

Note that the Ready to Transfer indication is on a team basis. Forexample, a Scada-Mate team member associated with two fields will showone Ready to Transfer indication for each field/team.

Rules for Source Selection

When a field has been deenergized due to a circuit event, the coach hasthe responsibility to find the best team member to use to restoreservice to the field. This source can be any open switch around thefield, including the source switch that originally tripped open. Thecoach must visit as many team members as necessary to collect theinformation needed to make this determination. The rules for theselection of an alternate source follow.

Overcurrent Detected

If an overcurrent was detected by the existing source switch (nowtripped open), the coach must first assume his field is faulted and setthe fault indication flag. He must then look for a load switch on hisfield that also detected an overcurrent. If he finds another team memberindicating overcurrent, the coach can assume the fault is downstream inan adjacent field, and clear the fault indication flag for his field.

This can be summarized as “A field is considered to contain a faultcondition if one and only one team switch on that field indicates anovercurrent fault.”

Note: Obviously the load-side team member that has detected anovercurrent must have the associated switch open to isolate the faultbefore the coach can restore service to the field.

If no load switch is found with an overcurrent indication, the faultmust be on the local field, and the coach must not restore service tothis field. At this point service can only be restored by humanintervention.

If an overcurrent indication was found on a load switch, the firstchoice for restoring service to the field should be the normal sourceswitch. The coach must first verify that all necessary load switches onthe field are open, then he should return to the normal source switch torequest a close operation from the player. If the player can close theswitch, the coach's primary responsibility is complete.

No Overcurrent Detected

If an overcurrent was not detected by the existing source switch, thecoach will immediately look to the first alternate source team member torestore service to the field. Using the Switch Availability Rules(below) the coach will determine whether the first alternate switch isavailable, and if not, continue searching through the alternate sourcesequence list. If none of the switches on the alternate source sequencelist are available, or the list is empty, the coach will use the SwitchAvailability Rules to search through all switches in the team.

When an acceptable switch is found, the coach will travel to that switchand ask the player to close the switch. If successful, the coach'sprimary responsibility is complete. If not, the coach will again searchfor another switch in the team to close.

If no acceptable switch is found, the coach will continue with othertasks as necessary, but also continue to look for a way to restoreservice to his field.

Basic Switch Availability Rules

The switch can be used as a good alternate source if:

-   -   the switch is presently open    -   the switch's normal job is a source, a tie, or a load/tie switch    -   the switch is in process enabled mode    -   the switch is active (indicated by a non-zero RTU address)

Note: If the normal source switch detected an overcurrent, and the fieldis NOT faulted, the highest priority switch to close will be the normalsource switch. The priority will then go to the alternate sequence list,followed by normal tie switches, and finally to load/tie switches.

Rules for Initiation of Return to Normal

The decision whether to initiate a return-to-normal (RTN) processdepends on the conditions within the team. Conditions that will causethe initiation of RTN include:

-   -   Correction of fault condition        -   The correction of the fault condition is signaled by the            return of stable 3-phase voltage to the normal source side            of the switch(es) directly downstream of the faulted line            section.    -   External request        -   An external request to start RTN may be received over            various communication channels or any other means where a            human can force the initiation regardless of the state of            the circuit.

Correction of Fault Condition

If a field is determined to be faulted, such that the field is also deadand a transfer event has taken place to restore adjacent fields, aprocess can be started to detect the restoration of this field byexternal forces (humans, scada, etc.). When this process has detected astable restoration, an event can be generated for the coach to receive.

The process will include the monitoring for return of voltage, and atimer to determine the stability of the voltage.

Rules for the Transfer and Return to Normal Processes

The rules for the operation of an individual switch are similar to thatas discussed in connection with the prior embodiment of FIGS. 1-9. Thefollowing is a list of the existing rules, modified only slightly. Thereare rules for single switch operation, dual switch operation, andrecloser operation.

Single Switch Transfer Rules:

-   -   A “tie” switch is any open switch that when closed will        reenergize a line section up to other open switches. A tie        switch may close even though it does not sense any voltage (as        would be the case if the voltage sensors were on the deenergized        side of the switch).    -   In order to close a local presently open switch, at least one        valid closed switch and one valid open switch must be detected        in the adjacent line sections. The following rules define the        conditions that must be met for the local switch to validate the        state of adjacent switches and line sections.    -   A presently open switch on the load side of a faulted line        section may close for the purpose of restoring load if:        -   a. no error conditions exist        -   b. the adjacent fault side switch is open        -   c. the adjacent fault side switch did not detect a fault,            but did see a loss of voltage        -   d. the current level seen by the adjacent fault side switch            before the outage is within configured and/or calculated            limits (or the maximum number of permitted line segments for            the circuit is within threshold)        -   e. an adjacent non-faulted side switch indicates it saw a            voltage loss and/or fault but it is now closed, or the            adjacent non-faulted side switch is a normally open switch,            or the adjacent non-faulted side switch is a breaker and            voltage has been restored (this step is bypassed if the            local switch is a normally open switch, and voltage checking            is disabled)        -   f. the local switch is a normally open switch, it may be            configured only close if good voltage is detected on its            voltage sensors on the alternate feeder side        -   g. the local switch has control of the tokens (Coaches) from            both adjacent line sections (Fields), if an adjacent line            section exists        -   h. the adjacent line section on the alternate source side is            directly associated with the alternate source, or the            adjacent alternate source side line sections have given            permission based on available capacity and present status.    -   A normally closed switch on the source side of a faulted line        section may reclose if:        -   a. no error conditions exist        -   b. at least one adjacent fault side switch detected a fault        -   c. the adjacent fault side switch that detected the fault is            open        -   d. the adjacent non-faulted side source switch indicates it            saw a voltage loss and/or fault but it is now closed, or the            non-faulted side is the breaker and voltage has been            restored        -   e. the local switch has control of the tokens (Coaches) from            both adjacent line sections (Fields), if an adjacent line            section exists

Single Switch Return to Normal Rules:

-   -   To be eligible for return to normal a device must be configured        as either “closed return” or “open return” in addition to no        error conditions and correct operating mode.    -   All devices must indicate that they are in a        return-to-normal-ready state before any action may occur. This        is confirmed through the sharing of data between line sections.    -   All voltage sensors on normally closed positions must be        installed on the source side of the switch, or the source side        device must inform the local device that return-to-normal may        start, or if this is the first device in a team a feeder monitor        device must be installed on the source side in order to inform        the local device that return-to-normal may begin.    -   Normal 3-phase voltage must be restored to the source side of a        normally closed device that is presently open for a minimum        threshold time before any activity begins. The presence of        3-phase voltage may be indicated through communications (see 3.        above).    -   An open device on the source side of an isolated fault must be        closed while remaining in automatic mode.    -   Any device placed in manual mode before returning to normal will        stop the return to normal process. All positions will need to be        manually set back to their normal state.    -   An open device must have control of the tokens from both        adjacent line sections, and the data associated with those        tokens must allow the close operation to occur.    -   A normally open device does not need control of both tokens in        order to reopen. This is the only exception to the “token        control” rule.    -   Any device not in its normal state may return to its normal        state by coordinating with other devices in the team by        following the rules stated below.        -   no error conditions exist        -   the normally open switch does not indicate a fault        -   during a closed transition, a normally closed device may not            reclose until it has received a verification from the            normally open device that it is ready to reopen        -   during a closed transition, a circuit parallel may not be            made until any reclosers in the team have indicated that the            settings in each recloser have been adjusted to handle the            parallel (i.e. disable ground relay)        -   during an open transition, a normally closed device may not            reclose until it has received a verification from the            normally open device that it is presently open        -   during a closed transition, a normally open device may not            reopen until all normally closed positions have reported            that they are presently closed        -   a normally closed device may reclose only if voltage is            present on all sensed phases, or if the source side device            is presently closed, or if a feeder monitoring device            reports 3-phase voltage has been restored        -   the local switch has control of the tokens (Coaches) from            both adjacent line sections (Fields), if an adjacent line            section exists    -   Note: During a closed transition, the normally open device must        reopen following the allowed transfer time whether it has heard        from the normally-closed but presently-open device or not. This        is done to prevent the parallel of lines for an extended period        of time.

Transfer/Reconfiguration Operating Rules for Dual Switches

-   -   1. All normally closed positions are configured to open on        voltage loss, with or without overcurrent detected. The        operation will take place after the specified count of breaker        operations.    -   2. All normally closed positions may be configured to open on        phase imbalance. The operation will occur if one or two phases        remain deenergized continuously for a time equal to the        configured threshold time. (standard phase loss protection        logic)    -   3. A “tie” position is any open position that when closed will        reenergize a line section up to other open switches/positions.    -   4. A dual switch device can operate one or both of its active        positions (TEAM enabled) simultaneously.    -   5. A dual switch device with a tie position on the load side of        a faulted line section will use the following external        conditions to determine whether it may close its tie position,        and its second open position if applicable, for the purpose of        restoring load.        -   a. no error conditions exist        -   b. the adjacent fault side switch is open        -   c. the adjacent fault side switch did not detect a fault,            but did see a loss of voltage        -   d. the current level seen by the adjacent fault side switch            before the outage is within configured and/or calculated            limits        -   e. an adjacent non-faulted side switch indicates it saw a            voltage loss and/or fault but it is now closed, or the            adjacent non-faulted side switch is a normally open switch,            or the adjacent non-faulted side switch is a breaker and            voltage has been restored            -   (this step is bypassed if the local switch is a normally                open switch, and voltage checking is disabled)        -   f. the local switch is a normally open switch, it may be            configured only close if good voltage is detected on its            voltage sensors on the alternate feeder side        -   g. the local switch has control of the tokens (Coaches) from            both adjacent line sections (Fields), if an adjacent line            section exists        -   h. the adjacent line section on the alternate source side is            directly associated with the alternate source, or the            adjacent alternate source side line sections have given            permission based on available capacity and present status    -   6. A dual switch device with a tie position on the load side of        a faulted line section will use the following internal        conditions to determine whether it may close its tie position,        and its second open position if applicable, for the purpose of        restoring load.        -   a. no error conditions exist        -   b. any active positions are open        -   c. no fault was detected locally        -   d. the current level seen by the adjacent fault side switch            before the outage is within configured and/or calculated            limits    -   8. A tie position may close even though it does not sense any        voltage, as would be the case if the voltage sensors were on the        deenergized side of the position. This rule does not include the        first switch out from the breaker.    -   9. If after closing the active positions the dual switch device        detects a loss of voltage (or voltage never returned) within a        time equal to the configured threshold time, the position        furthest from the alternate source will reopen (shots-to-lockout        logic). Also, if the position closest to the alternate source        detects a fault, that position will also open.    -   10. The active positions of dual switch device that were most        recently closed must remain closed for the shots-to-lockout time        threshold before the local device can inform other devices that        it has successfully completed its operations.    -   11. Normally closed active positions on the source side of a        faulted line section may reclose if the following external        conditions exist.        -   a. no error conditions exist        -   b. at least one adjacent fault side device detected a fault        -   c. the adjacent fault side device that detected the fault is            open        -   d. the adjacent non-faulted side source device indicates it            saw a voltage loss and/or fault but it is now closed, or the            non-faulted side is the breaker and voltage has been            restored, or the non-faulted side device is a feeder status            monitor and has informed the local device that the feeder is            energized        -   e. the local switch has control of the tokens (Coaches) from            both adjacent line sections (Fields), if an adjacent line            section exists    -   12. Normally closed active positions on the source side of a        faulted line section may reclose if the following internal        conditions exist.        -   a. no error conditions exist        -   b. a fault was detected internally by all active positions    -   13. If after closing the active positions the dual switch device        detects a loss of voltage within a time equal to the configured        threshold time, the position furthest from the source will        reopen (shots-to-lockout logic). Also, if the position closest        to the source detected a fault, that position will also open.    -   14. The active positions of dual switch device that were most        recently closed must remain closed for the shots-to-lockout time        threshold before the local device can inform other devices that        it has successfully completed its operations.    -   15. After an isolation/transfer event has occurred all closed        positions will operate using standard sectionalizing with phase        loss protection logic. (this of course follows any        shots-to-lockout logic that is necessary)

Additional Notes:

-   -   If a pad-mounted gear unit contains the normally open switch,        and also contains an active normally closed switch, it may be        allowed to transfer load regardless of the state of the team.        This follows the assumption that the most critical load is        closest to the alternate circuit. The critical load is fed from        the load position(s) of the padmount. This padmount would be        operating as simple source transfer to reenergize the critical        load.    -   SMM—mode enabled when there is actually only one member in the        team, or when a stop transfer has occured and the N.O. switch is        in a padmount that also has an active N.C. switch. There must be        a local record in SMM, but no other team records in the database        must be present. If other records are present they will be        disregarded for the period that SMM is active.        -   In such an SMM mode, RTN on voltage restoration will only            work if voltage sensor sets are on the source sides of the            padmount.

Return to Normal Rules for Dual Switches

-   -   1. To be eligible for return to normal a device must be        configured as either “closed return” or “open return” in        addition to no error conditions and correct operating mode.    -   2. All devices must indicate that they are in a        return-to-normal-ready state before any action may occur. This        is confirmed through the sharing of data between line sections.    -   3. All voltage sensors on normally closed positions must be        installed on the source side of the switch, or the source side        device must inform the local device that return-to-normal may        start, or if this is the first device in a team a feeder monitor        device must be installed on the source side in order to inform        the local device that return-to-normal may begin.    -   4. Normal 3-phase voltage must be restored to the source side of        a normally closed device that is presently open for a minimum        threshold time before any activity begins. The presense of        3-phase voltage may be indicated through communications (see 3.        above).    -   5. An open device on the source side of an isolated fault must        be closed using shots-to-lockout while in automatic mode.    -   6. Any device placed in manual mode before returning to normal        will stop the return to normal process. All positions will need        to be manually set back to their normal state.    -   7. An open device must have control of the tokens (coaches) from        both adjacent line sections, and the data associated with those        tokens must allow the close operation to occur.    -   8. A normally open device does not need control of both tokens        (coaches) in order to reopen. This is the only exception to the        “token control” rule.    -   9. Any device not in its normal state may return to its normal        state by coodinating with other devices in the team by following        the rules stated below.        -   a. no error conditions exist        -   b. no fault indications remain in any device        -   c. during a closed transition, a normally closed device may            not reclose until it has received a verification from the            normally open device that it is ready to reopen        -   d. during an open transition, a normally closed device may            not reclose until it has received a verification from the            normally open device that is presently open        -   e. during a closed transition, a normally open device may            not reopen until all normally closed positions have reported            that they are presently closed        -   f. a normally closed device may reclose only if voltage is            present on all sensed phases, or if the source side device            is presently closed, or if a feeder monitoring device            reports 3-phase voltage has been restored        -   g. the local switch has control of the tokens (Coaches) from            both adjacent line sections (Fields), if an adjacent line            section exists    -   Note: During a closed transition, the normally open device must        reopen following the allowed transfer time whether it has heard        from the normally-closed but presently-open device or not. This        is done to prevent the parallel of lines for an extended period        of time.    -   On a padmount control the process of determining whether RTN can        start must be a bit different. This is due to the possible        arrangement of voltage sensors. If there are voltage sensors on        both feeds, the sensors will be on the source side. While this        will make it possible to wait for stable voltage, which set of        voltage sensors to monitor is still an issue. If there is only        one set of voltage sensors they will be on the bus. This will        make it impossible to watch for stable voltage to return, so an        external indication is necessary. This external indication may        be the switch control on the source side, or it may be a        separate device altogether, feeding information into the team. A        separate device could also take the form of a human, through        SCADA or other means, telling the team to start RTN.

Recloser Specific Operating Rules

Normal Circuit Configuration

A team with one or more reclosers will be Ready to Transfer if:

-   -   All members of the team are in their normal states    -   All members have automatic operation enabled    -   No errors exist (internal, comm, sync, etc.)    -   All recloser members are using the preconfigured settings group

Each Add-on board will monitor the settings group associated with itslocal recloser. The settings group consists of:

-   -   Ground Trip Block    -   Reclosing Block    -   Cold Load Pickup Block    -   Voltage Trip Block    -   Fast Trip Block    -   Normal Profile    -   Alternate Profile 1    -   Alternate Profile 2    -   Alternate Profile 3 (switch mode)

Reconfigured Circuit

-   -   When the circuit is in a reconfigured state (post-transfer,        pre-RTN) a change to the settings group monitored by the Add-on        board will only postpone the Return-to-Normal operation. Unlike        disabling and then reenabling automatic operation when in a        Ready-to-RTN state (which forces manual return of the team),        temporarily modifying the settings group only causes a temporary        stop transfer condition. Once the settings group is returned to        the expected values the team will return to Ready-to-RTN mode.    -   In this way changes to the settings group is similar to a Block        Supervisory or Hot Line Tag command, i.e. similar to a visual        disconnect on switch controls such as ScadaMate Switches. In all        these cases Return-to-Normal is allowed to continue when the        setting/state is returned to its normal position.    -   One example of this might be when a closed recloser being        backfed from an alternate circuit is put in non-reclosing mode        while some work is being done on the line. Non-reclosing is not        the normal state for the reconfigured settings group. While this        recloser is in non-reclosing mode Return-to-Normal will not be        allowed to begin at any point within the team, regardless of        whether voltage has returned from the preferred circuit. Once        reclosing is again allowed on that recloser Return-to-Normal can        continue. If voltage had already returned at that point the        Return-to-Normal Delay Timer would begin to time down, or the        team would just continue to wait for voltage to return.    -   Another example would be at the recloser that is presently open        isolating the fault. When the fault is repaired the user will        want to close the recloser using non-reclosing. He first sets        non-reclosing, then closes the recloser. Assuming the recloser        stayed closed, the user would be expected to reenable reclosing        before the Return-to-Normal Delay Timer would begin timing down        at the next isolating switch down stream. If he left        non-reclosing active the team would never return to normal. If        the crew decided to return the team to normal manually, but they        left non-reclosing active at this recloser, the team would never        become ready to transfer, even though the team is in its normal        state. The team would only become ready to transfer after the        reclosing was again enabled at that recloser.

Changing Recloser Profile

-   -   It is important that the circuit is stable when changing the        recloser's protection profile. The profile should only be        changed when there is no automatic team activity scheduled, and        the load is not above the minimum trip setting. A DNP Binary        Input “Above minimum trip” may be used as one verification that        the profile may be changed. While this point is not a reliable        indication of faults, it can be used for this purpose.    -   The recloser's protection profile is changed from its normal        value only when the recloser is being energized from the        alternate circuit. The profile is changed just prior to closing        the recloser to backfeed a line section. The profile is not        changed on reclosers on the alternate circuit, or reclosers on        the normal source-side of the fault. Because the recloser is        open when the profile is changed, and because the transfer        process is state driven, the time to change the profile is        easily determined, and easily controlled.    -   The operation can be less predictable when returning the circuit        back to its normal configuration. A recloser that is presently        closed, backfeeding a line section, and in an alternate        protection profile, does not have a specific state defined to        return to its normal profile. Additionally, the process changes        based on open or closed transitions. So, the point that provides        the most stable and consistent time to change profiles during        the return to normal process is at the end of the process.    -   Since the end of the return to normal process may be from        seconds to minutes after all switches are actually stable in        their normal positions (depending on the Transfer Process Time        Limit), it is important to base the time of returning the        profile on the state of all team members. Because the normally        open switch is the only switch in the team to be informed of all        team activity during the return process, the normally open        switch will also be required to inform all team members when the        team is back to normal and stable. To do this an additional step        will be added to the return to normal process. At this time this        step will only be associated with the normally open switch and        any reclosers in the team.    -   The normally open switch will enter this step after it        successfully reopens, and remain in that step until it knows all        team members are back to normal. At that point the normally open        switch will broadcast a message to all other team members        informing them that the team is stable.    -   Any reclosers will enter this step either immediately if the        recloser is already in its normal state, or after it has        successfully returned to its normal state. When the message is        received that the team is now back to normal and stable, the        Add-on board will signal the recloser to change its protection        profile. The transition back to the normal profile will be        verified in the “end transfer” task following the timeout of the        transfer process timer.

In accordance with important aspects of the present invention andreferring now additionally to FIGS. 15-21, depicted therein arerepresentations of system operation and response to an Overcurrent FaultEvent occurring between two Switches 5 and 6 in the illustrativedistribution system depicted in FIGS. 15-21. The following describes theresponse of the present invention to reconfigure and restore service:

FIG. 16: An overcurrent fault occurs between switches 5 and 6 on FieldA, causing operations of the breaker on feeder 22. Fields A, B and D areall affected, but only switches 6 and 7 detect the overcurrentcondition.

FIG. 17: Switches 6 and 7 both open on 2 counts of voltage loss withovercurrent. The breaker on feeder 22 closes back into open switch 7 andholds good. At this point Field A truly has a faulted line condition,but Field B only thinks it has a faulted line condition.

FIG. 18: Switch 9 is configured for 3 counts of voltage loss withoutfault, so it is presently waiting for an extended voltage loss in orderto trip open. In the mean time, Team Coaches on Fields A, B and D areall trying to restore service to load within their fields.

FIG. 19: The coach's job on Field A is easy. He can determine the faultis within his field and simply prevent the closing of either switches 5or 6. Likewise, the coach on Field D can do nothing until asectionalizing event has taken place, so he is waiting for theexpiration of the extended voltage loss timer in switch 9.

FIG. 20: The coach on Field B, on the other hand, can use his teammembers to save the day. Coach B knows that the overcurrent was detectedby both switches 6 and 7, so he knows the fault is not within Field B.His first choice for restoring service to the field is the normalsource, so he visits switch 7 to see if service has been restored fromthe source.

FIG. 21: Coach B finds that switch 7 is energized and ready to close.With no other coach to consult with, and no problem within his field,Coach B closes switch 7. This immediately restores all of Field B loadfrom the normal source, and restores service to Field D so that switch 9no longer needs to sectionalize. Field A is left to be repaired andreturned to its normal state manually.

In accordance with important aspects of the present invention andreferring now additionally to FIG. 22, described therein is anillustrative flow diagram that may be employed and representative oftypical operations performed by the present invention of FIGS. 12-15 ata single team member or player. The various tasks called out therein areperformed only while a coach is present. In this way, the coach cansupervise the process and also leave after a sutiable visit time withupdated global data including an updated events list. Some of the basicfunctional requirements applicable to and achieved by the transfer tasksof this flow diagram include:

1—The switch shall only close, if all automatic-mode switches areopened. Each field is only responsible for seeking its source. Allswitches in a field must be opened, to conform with the “transfer”method of allocating one fields' load at a time, to a source. However,non-automatic-mode switches in the field may be closed, because of useraction. In this case, the field shall add this switches' “other” field”load to the field's load requirements. If any Source switch trips opendue to sectionalizing or to loss of source (extended volt loss) then allswitches in that field will trip open, since the sectionalizing logicwill trip open all switches downstream of the faulted switch. Therefore,if an overcurrent fault occurs within the field or upstream of thefield, the source switch will trip open on this fault. Since all otherfield nodes are downstream of this fault, they will trip open throughsectionalizing logic. An extended Loss of Energy timer condition (LOE)also causes switches to be opened through a process called acceleratedtripping.

Therefore, if the field loses source, then all switches are positionedopen for a transfer of source, excepting the manually closed (nonDAT-auto-mode) switches.

2—A switch shall close only its negotiated-source switch. Reason: theload switches are closed by their field's Coach after a negotiationprocess.

3—The switch shall only close if the following conditions are true:

-   -   a. no error conditions exist and the requesting field isn't        faulted. The Coach should check the latter condition; this is a        double check. Obviously, the logic should seek a source if it is        faulted.    -   b. all switches in the field are open (non-automatic nodes are        ignored)    -   c. the field granting the source isn't open due to a overcurrent        sectionalizing condition, within the field; this is checked by        determining if the switch has energy (voltage).    -   d. the Coach of the field granting this source is present and        the Coach of the requesting field is also present. This ensures        synchronized access to this field's ampacity allocation. Because        this task has control of the processor, that Coach can't move on        to another, until this task is complete    -   e. the field granting the source has sufficient capacity within        that field's local and global restrictions and the granting        field can allocate a line segment from the circuit's spare pool.

Considering the Return to Normal Process tasks as shown in the flowchart of FIG. 22, some of the basic functional requirements (i.e. ruleset) applicable to and achieved by the transfer tasks of this flowdiagram include:

Two events causing a Return To Normal process:

1) A Coach attempts to restore an open switch state to its previousclose state, after detecting voltage present, following the expirationof a Loss of Energy timer.

2) A Lineman or SCADA operator closes one of two open switches thatbracket a faulted line segment—this cause the other open switch to seekan Return To Normal, since it should be closed, yet it is energized,with no fault present.

In both cases, the software must close the switch AND open the normallyopen switch that must exist between the switch and its present source.This requires travel to the normally open switch to either open it (opentransition) or set a timer to open it (close transition), and thentravel back to the switch requiring a close to close it. And then travelback to the normally open switch to open it and cancel the timer. Thetravel direction will always be towards the present source, whentraveling to the normally open switch and towards the RTN source whentraveling to the switch that desires a close. So, first travel in thepresent source direction to the normally open switch, by selecting thisswitch's field that doesn't have this switch as its source switch; thismust be the source field of the switch's “source switch” field.

In accordance with important aspects of the present invention andreferring now additionally to FIGS. 23-55, there is depictedrepresentations of system operation and response of the presentinvention to the loss of a substation identified as S1, e.g. due totransmission failure. The following notes apply to explaining the systemresponse:

General Notes:

Notes on Coach Management

A coach has a coach ID number and an incrementing visit counter.Normally the coach roams the field at will. He must visit every teammember in a prescribed period of time though. If he arrives at a teammember that has already received that ID and visit counter (the countermust be greater than the last if the ID is the same), the coach assumeshe is a duplicate and dies. If the coach arrives to find another coachwith a higher ID has visited, again, this coach dies. If a team memberdoes not hear from the coach within a prescribed period (2× the visittime), that team member can spawn a new coach with an ID number onehigher than the last coach he heard from, and a new visit counter. Thenew coach must determine the state of the field and begin to take actionif necessary.

Notes on Event Initiation

When an event begins, any team member that has witnessed the event maycall out to the coach and the other team members within that field. Thiscall includes a sequence number, the nature of the event, and which teammember made the call. Each team member contains a process thatcontinually monitors for these calls. If the call is to restore serviceto the local field, the coach must first visit the other normally closedteam members to verify that they are open. Then he will move to normallyopen switches that can be used to restore service, going to the FirstAlternate if configured. If the call is to allow service to be restoredto an adjacent field, the coach will immediately move to the callingteam member.

Notes on Loading Restrictions

The decision to restore a field (circuit segment) based only on loadingwill be done without prior contract for those resources. The criteriawill be the available ampacity of the feeder, updated as thereconfiguration progresses, and any restrictions placed on a field dueto wire size or other limiting factors. The lesser of the two will beused. Note that the loading information is assumed to be up to date andaccurate. This method does not prevent the overloading of a circuit whendisjoint fields (such as on a bifurcated circuit) assume the loadinginformation is correct, and both close to restore independent loads atthe same time, or near to the same time.

Notes on Segment Restrictions

The decision to restore a field when a segment restriction has beenconfigured requires prior contract for the resource. This involvessetting a simple lock if the adjacent field is the field with thesegment restriction. If the field with the segment restriction isfurther toward the source, a coach may need to daisy chain, possiblythrough more than one field, down to field with the restriction in orderto verify the resource still exists. He may then secure a contract forthe resource. This may add time to the restoration process, but isnecessary to prevent the overload of a feeder.

Notes on Return to Normal

-   -   The configuration of open or closed transition back to normal is        an attribute of an individual team member.    -   Fields with no normally open switches do not get configured for        open or closed transitions at all. They must follow the needs of        the adjacent fields.    -   During a return to normal sequence, a normally closed switch        between fields where an open transition will be required will        remain closed. It will relay the RTN request, become        deenergized, and relay the go-ahead message back before finally        being reenergized from the normal source.    -   During a return to normal sequence, a normally open switch that        is configured to use a closed transition, but is presently        limited by another switch requiring an open transition, will        reopen immediately. This is the appropriate action since the        source side field will be deenergized anyway when the open        transition switch opens. It will also allow the source side        field to complete its RTN operation sooner.        Specific Notes on FIGS. 24-55:

FIG. 24: Each feeder is limited to 600 amps of emergency capacity. Thisis the limiting factor for the first field on each feeder. Forsimplicity, each field has a peak loading of 100 amps, but at the timeof the event every field was loaded only to 50 amps. Some restrictionson capacity and circuit segments will be included in a later Figure.

FIG. 25: The loss of transmission feeding substation S1 has left feedersF11, F12, and F13 without service. With no reclose counts, each of thesectionalizing switches can only wait for their extended voltage losslogic to time out and cause the switches to open. As soon as the eventbegan, though, the loading averaging stopped so that the load prior tothe event would be used during the reconfiguration process.

FIG. 26: Since there is presently 50 amps on each field in the system(for simplicities sake), and there are no other limitations configuredby the user other than the original 600 amp limitation on the feeder,the available capacity of each of the alternate feeders can be easilydetermined. The available capacity of each of the fields on thealternate circuits is indicated below.

FIG. 27: For illustrative purposes, assume that the user has placedampacity restrictions on some of the fields. There is still 50 amps oneach field in the system, but fields K and T are each configured with anampacity restriction of 300 amps.

FIG. 28: Also for illustrative purposes, assume that the user has placedadditional circuit segment restrictions on field I. Fields downstreamare limited by this “remote” restriction, therefore they must verify theavailability of segments to add, and place a contract on that resource.

FIG. 29: Based on the foregoing, the extended voltage loss timers haveexpired causing all normally closed switches on feeders F11, F12 and F13to open.

FIG. 30: Where only one normally open switch exists in a field, thatswitch becomes the “First Alternate” by default. Where a field has morethan one normally open switch (field Q), the “First Alternate” can beconfigured by the user if desired. A field with no normally openswitches will take service from where ever he can get it. The arrowsindicate the likely movement of the coaches when the event begins, basedon the rules for coaches.

FIG. 31: When the coach arrives at the switch that he would like toclose, if the coach from the adjacent field is not already there, he canmake a call to that coach to alert him. The coach will travel to theteam member from where the call was made. With both coaches at theswitch, a decision can be made as to whether to close the switch.

FIG. 32: At switches 2, 5, 8 and 29, the restoring field has plenty ofcapacity, and no other restrictions, so those switches may closeimmediately. Although the loading is acceptable, the coach for field Kknows that only one segment may be picked up by feeder 32 (as configuredin Field I). Therefore, the coach for K must verify the segment is stillavailable, and secure a contract for that segment, with field I.

FIG. 33: Coach K moves to switch 16 and calls for coach I. With the twocoaches at switch 16 it is determined that no contract exists for theone line segment. At the same time, coaches for fields O and P arelooking for restoration service from the alternate fields. Field P gotthe attention of coach Q first, so both coaches are now at switch 39.Since field Q also had 50 amps on it, the available capacity of field Qis now 450 amps, with no other restrictions. Therefore, switch 39 canclose.

FIG. 34: With a contract for the one line segment secured, coach K canmove back to switch 20, where a decision can now be made to close theswitch. Note the movement of coach O back to switch 24 in an attempt tofind a good source to restore service to his field.

FIG. 35: Coach L now moves to switch 22 where coach N is trying to getservice restored. This request is denied by coach L based on the segmentrestriction. The same thing happens at switch 24.

Coach P can also move to switch 27 where it can decide to restoreservice on its own, since there is no adjacent field.

FIG. 36: Coach O again moves back to switch 28. With plenty of capacityon field Q, and no other restrictions, coaches O and Q are able to makethe quick decision to close switch 28.

Coach P, also knowing of the same present available capacity, decides toclose switch 27. Notice the lack of prior coordination between fieldsallowed load to be picked up simultaneously, possibly overloading thefeeder.

FIG. 37: Notice that the only load that was unable to be restored wasField N. Also notice the updating of the available capacity on feedersthat were used to restore service.

FIG. 38: With so much of the load restored, a number of switches feelthat they should start the Return to Normal process. Switches 4, 23 and24 are in this category. While the RTN timer can count down, RTN is notallowed to begin due to the two-coach rule. A coach that knows his fieldis not being fed from its normal source will not allow a coach from anadjacent field to start RTN.

FIG. 39: The transmission system is now restored, providing service tosubstation S1 and feeders F11, F12 and F13. Switches 1, 25 and 26 cannow begin to time down their RTN timers.

FIG. 40: The RTN timers expire, allowing the coaches to begin theprocess of returning each field to normal. Field Q is configured for anOpen transition, while all the other fields that include normally openswitches are configured for Closed transitions. The RTN process musttake place first at the fields closest to the normal source, then workoutwardly. A Closed transition RTN requires notification of the normallyopen switch before it may continue (M-Situation).

FIG. 41: Although the RTN process will be occurring simultaneously onthe three feeders, let's talk about feeder 11 by itself first. Coach Bfinds out at switch 1 that the RTN process can start. Since it is aclosed transition he must notify normally open switch 2. Thisnotification starts a timer in switch 2 which will force it to openafter a prescribed timeout. This insures that a circuit parallel can notbe left in place indefinitely, but it is expected that switch 2 will beopened prior to the timeout by the RTN process.

FIG. 42: With an acknowledgement back from switch 2, switch 1 can nowclose.

FIG. 43: Coach B can now move back to switch 2 to force the openoperation. This open operation does not require the “two coach” rule.

FIG. 44: Coach B then moves on to any normally closed but presently openload side switches. Field C has been ready to RTN since the source sideof switch 4 was reenergized by field B. Both coaches B and C arrive atswitch 4. Since the RTN timer had timed out earlier, only thenotification process is needed.

FIG. 45: Coach C moves to switch 5 to notify of the impending RTNprocess. Switch 5 starts the “M-Situation Timer.”

FIG. 46: Coach C then moves back to switch 4 where the decision can bemade to close. Field B is now back to normal.

FIG. 47: Coach C quickly moves again back to switch 5 where it can openthe switch immediately. Field C is now also back to normal.

Notice that the available capacity on fields A, D, E and F are allupdated soon after these operations.

FIG. 48: At the same time as feeder 11 was returning to normal, feeders12 and 13 were performing similar actions. In this case, though, field Qrequires an Open transition back to normal. To accommodate this coachesO and P must get approval from all their presently closed team membersthat are connected to other fields before closing their normal sourceswitches. Switch 28 denies the request because switch 29 requires anopen transition.

FIG. 49: Since switch 39 is normally open, and it knows a normally openswitch that requires an open transition is closed in field Q, it willopen immediately in order to facilitate the RTN process on field P.After receiving this request for RTN, the coach on field Q can move toswitch 29 to perform the open there. Load is ultimately dropped on allthree fields O, P and Q.

FIG. 50: Coach P can quickly move back to switch 26 to close, returningfield P back to normal right away. Coach Q may then move back to switch28 to approve the RTN request.

FIG. 51: Coach O can now move to switch 25, close it, restoring serviceto fields O and Q. Field Q is now also back to its normal state. Noticethe available capacity for feeder 41 gets updated.

FIG. 52: Now coach O moves to switch 24. The “M-Situation Timer” processis completed by coach L, and switch 24 is allowed to close. Field O isnow back to normal.

FIG. 53: Coach L moves to switch 20 to open that normally open switch,then goes to switch 22.

At switch 22 coaches L and N can make the determination to closeimmediately, since there is no field on the load side of field N.

FIG. 54: Three areas of activity are now occurring. 1) Coach N is ableto go to switch 21 and immediately close, returning field N back tonormal. 2) Coach K moves to switch 16 to remove the contract with fieldI for the one line segment. 3) And Coach L moves to switch 23 to allowthe RTN process to commence. After Coach M sets the “M-Situation Timer”in switch 8, switch 23 is able to close.

FIG. 55: Finally, coach M moves back to switch 8 to open it. The systemis now back to normal.

System Resource Allocation Methodology

Considering now additional aspects and features of the present inventionto provide system resource allocation methodology, e.g. to prevent theoverloading of electrical power sources, resources are provided at eachnode and communications of source allocation data or messages areperformed to other nodes to request and establish an appropriateallocation of system resources. For illustrative purposes, thismethodology will be described in connection with team members or playersalthough it should be understood that the methodology may also beimplemented in systems of nodes and individual node controllers 206without the definition of multiple teams. Also for illustrative purposesfor simplicity of explanation but not to be interpreted in any limitingsense, the resources and the methodology will be referred to as“Contracts” and “Contract Agents”. The “Contract Agents” (or CA'shereafter) facilitate the use of the Contracts methodology. The CA,implemented as an autonomous processing task, i.e. independent of theCoach functionality and the Player functionality that manages the localswitch, is employed to manage both the addition of load during loadtransfer, and the reduction of load on return-to-normal. Thus, the CAmay be characterized as a process that is active or enabled in eachswitch control and that manages only “Contract-related activities” asdescribed hereinafter. The CA functions by communicating locally withthe Player task, and remotely with other CA's via CA-specific messages.It should also be understood that while the CA will be discussed inconnection with a single-switch configuration, the CA is applicable toall devices such as dual switches, reclosers, etc.

If the user of the system has specified load pickup based on loadingrestrictions in terms of a segment count, the CA will be active tocontrol the management of the line segment restrictions. The CA is alsoactive if a valid line segment limit has been announced (propagateddown) from the source. The line segment limit is continuously propagatedout from the source (field) as the coach travels from team player toteam player, as an independent process. As the line segment limitpropagates outward (from the source field), lower set counts of linesegment limits take precedence and are then propagated further. If loadrestrictions have been set based upon maximum amperage, the CA is thenactive in response to this setting. The discussion of the CAfunctionality hereinafter is based on one of these settings orspecifications such that the CA functionality has been enabled. Itshould be noted that even with the CA functionality enabled, the Playerdoes not request a Contract unless the circuit segment being energizedis being fed from an alternate source, either directly or indirectly.For example, the closing of a source/sub switch (the team switch closestto the circuit's source) would never require a Contract, but the closingof a tie switch (between sources) would always require a Contract.Beyond these two absolute cases the general rule (as will be explainedin more detail hereinafter) is that a Contract is required if thepresent source Field, or granting Field, indicates it is being fed froman alternate source.

The indication of alternate source is initially set by the Coach thatcloses a normally-open tie switch. From that point the indication ofalternate source is propagated out each time an additional circuitsegment is restored. This way all teams will know they are on analternate source, even if the switch that was closed to restore servicewas the normal source switch for that field (for example switched radialtap lines).

The logic at the Player (team member) level requires that if thegranting field is already fed by an alternate source, or the localswitch is a “last-load-only” position and the requesting field is beingfed from an alternate source, or the local switch is a tie switch forthe requesting field, the Coach will be informed so that he/she can takeappropriate action regarding transfer restrictions. In this way an“alternate-source” flag (condition/indication) will propagate asnecessary to subsequent fields energized from the same alternate source.

When the alternate-source flag is set, the Coach also performs a task(running on a periodic basis) to initiate a check for the ability toremove the alternate-source flag (condition). Since this task requiresinformation from an adjacent team, the Coach will request the Player toperform the check and report back. The Player will look to see whetherthis switch on the requesting field is not a tie switch, and the otherfield still has its alternate source flag set, or, if this switch is alast-load-only switch and this field still has its alternate-source flagset, or, if this is a tie switch on the requesting field and currentswitch state is still closed. If any of these conditions are true thePlayer reports back that the Coach must continue checking. Otherwise thereport is that the alternate-source flag may be cleared.

In order for the clearing process to begin the flag must be cleared atthe normal7ly-open switch first. During the return-to-normal process,when a normally-open switch is able to reopen, the alternate-source flagcan be cleared without question.

The CA functionality interacts in the Player (team member) functionality(logic flow) that evaluates the rules for transfer when attempting toclose a switch to pick up load from an alternate source (e.g. after thelogic has proceeded through FIG. 22 a to FIG. 22 b, at the YES outputflow of the “Is Switch Open . . . ” decision block). If the CAfunctionality is enabled, and all the rules for transfer have beensatisfied, the Player task requests a Contract from the CA, suspendingload pickup until it has been notified by the CA of Contract acceptance.Upon receipt of the requested Contract, the Player task then resumes andcloses the switch (e.g. Player logic flow proceed in FIG. 22 b throughconnector C to the “Post Event=‘OK to close’ ” process block). It shouldalso be noted that as part of the Contract negotiation process, variouserrors (involving request rejection or timeout as will be explained inmore detail hereinafter) may occur that prevent the Contract from beinggranted. In the preferred embodiment of the invention, the Playernotifies the Coach of the failure status and the Coach is free to decidewhether to retry the request or to take some other action.

To better understand the methodology of the resource allocation featureof the present invention as characterized by the Contract Agent, thefollowing terminology/definitions are useful for illustrative purposes:

Contract Terminology:

-   -   Contract—A data structure that contains a record of the        allocation (or request for allocation or maintenance) of limited        available source capacity to distribution loads. The data        structure contains a characterization of the resource whose        allocation is to be controlled, plus related information        necessary to build and maintain a record of that allocation. The        data structure also contains a routing table that allows the        Contract to be transmitted back and forth between the Contract        Requestor and the Contract Grantor. Description of this data        structure follows hereinafter.    -   Contract Requestor (CR)—A team member that has determined that a        Contract is needed and then initiates the request to create the        Contract.    -   Contract Grantor (CG)—The CA which resides at the closest Player        in the closest Field to the resource (typically the source or        alternate source which is presently feeding the circuit).    -   Contract Intermediary (CI)—A CA which is neither the CR or CG        but which is in-between the CR and CG.    -   Contract Transaction (CT)—A message including a copy of a        Contract that is in some state of processing (requested, waiting        for acceptance, etc.). The purpose and processing of the        transaction is implied from the contents of the Contract State        field (see “8. Contract State” of Contract Data Elements        hereinafter).

Contract Agent Functionality Overview

In a distributed processing environment, the CA is effective to:

-   -   Traverse a distribution circuit from a point requiring the        allocation of a critical resource (Contract Requestor or CR), in        this case available capacity, to a uniquely defined point of        supply (Contract Grantor or CG).    -   Check for available capacity at all intermediate points along        the way (Contract Intermediary or CI), tracing the route from CR        to CG.    -   Check for available capacity along the entire route from CR to        CG and to only allocate the capacity once it has been determined        that the capacity can be accommodated along the entire route.    -   Reliably allocate, maintain and deallocate the resource.    -   Determine at intermediate points along the route of an active        Contract that the Contract is no longer needed and to propagate        the need to dissolve the Contract in one or two directions        simultaneously if necessary.    -   Keep active contracts alive by having the CR periodically        transmit a keep alive message to CI's and the CG with a minimum        of message passing in an error-free communication environment.    -   More reliably recover from lost messages by sharing the ultimate        responsibility (to maintain Contracts) between all participating        CA's through the use of parallel activity timers and recovery        logic.    -   To restore a lost contract rather than just remove it, allowing        the restoration to be triggered at any participating CA.    -   Reduce the possibility of redundant Contracts through adequate        identification and the propagation of a creation time/date stamp        throughout the Contract's area of travel.

Contract Data Elements

The data elements that form the contents of a Contract are:

-   -   1. Maintenance Timer. A countdown counter initialized to a        predefined maintenance interval. The duration of the timer is        based on the state of the contract and the action being        performed. The timer is decremented by the CA independently for        each active Contract and when it reaches zero, a Contract        maintenance request message is initiated.    -   2. Requesting Agent ID. The identity (communication address) of        the CA that originated the Contract request.    -   3. Granting Agent ID. The identity (communication address) of        the CA that granted the Contract request. Either or both        requestor and grantor agents may reside on Fields that are        external to an intermediate CA and its associated Contract        database. That is, there may be many Fields separating        requesting and granting CA's, and a modified copy of the        Contract will reside at each intermediate CA.    -   4. Requesting Field Number. The Field ID of the Field that        originally caused the Contract request.    -   5. Temporary Field Number. A Field number which may frequently        be the number of the Field the contract just passed through,        aiding in the building of the contract route, but which may be        used for other purposes in certain cases.    -   6. Contract Quantity. Number of resources (line segments)        Contracted for.    -   7. Contract Capacity. Amount of capacity in units of 10 amps        that are to be allocated or associated with the Contract.    -   8. Contract State. Present status of the Contract. The Contract        State may indicate the Contract is new and still in the        negotiating stage, it has been rejected by the granting CA, is        an active and valid Contract, or is being dissolved. A complete        list of these states is below:        -   a. Contract Active. A Contract request has been granted, and            is stored in this state at the CG, any CI's, and at the CR,            until further action is necessary (i.e. maintenance,            dissolve).        -   b. Contract Request Pending. A Contract request has been            issued and the requesting CA is now waiting for a response            from the granting CA.        -   c. Contract Request Unsent. A Contract request has been made            by the Player, has been accepted by the CA and is now            waiting to be sent toward the CG.        -   d. Contract Request Travel. A Contract has been requested            and the CA is now sending this request toward a potential            CG.        -   e. Contract Request Accepted. The grantor has accepted a            Contract for the requested resource. The resource is now            reserved for use. This status is passed to all CA's along            the path traversed from the grantor to the requestor and the            contract is then stored at each CA as Contract Active. When            received by the CR this state is communicated to the Player,            allowing the switch to be closed.        -   f. Contract Request Declined. This status will appear in            Contracts sent from any CA that determines that the Contract            request must be rejected.        -   g. Contract Request Declined. This status will appear in            Contracts sent from any CA that determines that the Contract            request must be rejected.        -   h. Contract Request Decline Continue. This status is a            placeholder that allows a CA that is (so far unsuccessfully)            attempting to send a decline message to the requesting CA,            to remember to resend the message later.        -   i. Contract Dissolve Start. This status is present in a            Contract at a CA that determines that the Contract should be            eliminated.        -   j. Contract Dissolve Continue. This status is present in            Contracts passed along from the CR to the CG.        -   k. Contract Maintenance Start. This status is present at a            CA that is the originator of an active Contract whose            maintenance timer has timed out, or has been tickled, thus            triggering the start of a maintenance sequence.        -   l. Contract Maintenance Tickle. If an intermediate CA for an            active Contract determines that maintenance needs to be            performed, it can request (tickle) the CA that originally            requested the Contract to begin a maintenance sequence.        -   m. Contract Maintenance Travel. This status is present in a            Contract that is being sent from its originating source to            other Contract Agents (containing copies of the Contract)            for the purpose of satisfying the Contract's maintenance            timer.        -   n. Contract Maintenance Travel Not Found. A CR has sent a            Contract Maintenance Request to a CI or CG which has no            record of the Contract and this information is being            returned to the CR.        -   o. Contract Maintenance Travel Return Not Found. This status            is present in a Contract which is being sent from a CA            which, in response to a Contract Maintenance Travel message,            has been unable to find the Contract. Upon receipt of the            message by the Contract Requestor CA, the request for a            Contract will be reissued.        -   p. Contract Maintenance Tickle Not Found. This status is            present in a Contract sent back to the originator of a            Tickle when another CA receiving the Tickle is also missing            the associated Contract.        -   q. Contract Maintenance Tickle Return Not Found. This status            is present in a Contract sent back to the originator of a            Tickle request when the Contract at the destination CA was            not found. This will cause the Contract in the intermediate            CA to be dissolved.        -   r. Contract Maintenance Reactivate. This status is found in            Contracts sent from a CA which has received a message            indicating that an existing, accepted Contract is no longer            present. The status will cause all receiving CA's to            reactivate the Contract, and pass along the reactivate            request to the previous CG. The reactivate request will            cause a reallocation of the resources to meet the Contract            requirements.        -   s. Contract Maintenance Reactivate Continue. This status            will appear as a placeholder in a Contract that cannot be            reactivated because the CA is busy, and will cause the            Reactivate to be retried later. This status is also used            when the Contract is at a Contract Agent that did not lose            the Contract, thus it must not reactivate the Contract, but            will only continue to forward the Contract toward the CG.    -   9. Contract Timestamp The timestamp may be used for both        Contract identification, and for Contract timing purposes. (In a        preferred embodiment, a 4-byte timestamp in UNIX format        corresponding to the time the original Contract was requested).    -   10. Contract Route Count. The number of Contract Agents that had        to be traversed to reach the granting agent from the originator.        The identity (communication address) of each CA along this route        that must be traversed to reach from the requestor CA to the        grantor CA is stored in the Contract Routing Table (see        hereinafter).    -   11. Contract Route Direction. In each copy of the Contract, this        is the direction within the Contract Routing Table (see below)        that must be traversed to move the Contract along its route to        completion. Initially the Contract is moved Up from the        requestor towards the grantor, and when granted, the Contract is        moved Down toward the requester.    -   12. Contract Routing Table. A list of CA identities        (communication addresses) that must be traversed to go from the        requestor CA to the grantor CA.    -   13. Contract Route Field Numbers. A list of field numbers        associated with each Contract Agent listed in the Contract        Routing Table.

Additional Notes on the Contract Data Elements

In an illustrative example of the preferred embodiment, the CA ID'sabove are simply the communication address of the team member at whichthe CA resides. Since the team member may take part in two or moreFields, and there is only a single CA at each team member, the Fieldnumber must be included to further qualify the identification of the CA.

The time that the Contract was originally requested at the CR serves twopurposes. It is used to uniquely identify the Contract (along with CAIDs and Field number). Unique identification of the Contract is usedduring maintenance of the Contract to be sure the Contract still existsin the locations where it is supposed to exist. In a modification to thepresent implementation the Contract time may also be used to determinethe maintenance interval and mortality of the Contract.

The routing table included in the Contract is a simple list of theswitch control RTU addresses that, when combined, will form the pathbetween the CR and the CG. This creates a simple, connect-the-dots formof routing. Initially the only routing data that is known is thestarting team member and the present source of each Field. TheContract's route during the first pass to the ultimate present sourceField is along the path of present source team members. Thecommunication address of each present source team member on each Fieldthrough which the Contract passes is appended to the Contract routingtable. When the Contract arrives at the ultimate source Field (CG) itwill contain all the information necessary to route both directions,regardless of the present state of the system.

In an illustrative implementation of the preferred embodiment, therouting table has finite resources, and cannot store an unlimited amountof routing information. If during the course of routing back to thepresent source a CA finds that the routing table has overflowed, the CAmust reject the Contract and route it back to the origin. The coach onthe requesting Field will ultimately be notified through the Player andmust then look for another alternate source.

Similarly, the number of Contracts that can be stored is also limited.If there is no room to store a new Contract in any CA, that CA mustdecline the Contract and return a “decline” CT back to its origin. Ofcourse, it should be realized that sufficient space is provided for allrelevant possibilities.

The Field associated with each Contract route is saved in the Contractrecord as a required value in the data transmit process, and allows theCA to update the line segment count in the Coach record.

Contract Processing Overview

The CA's primary goal is to manage its local database of Contracts. Thismanagement includes the job of accepting a Player's request for a newContract, obtaining control over the Contracted resource bycommunicating through CI's to a potential CG, maintaining the integrityof Contracts once issued, and dissolving Contracts once they are nolonger needed. The CA's resources for doing this consists of a Contractdatabase containing Contract records, a CT which allows the CA to conveyContract information to other CA's, and the Field database.

When a Contract is needed the Player makes a request to the CA to obtainthe Contract. The CA creates a CT including a copy of a “draft” versionof the Contract with all available information filled in, and sends ittoward the present source, normally all the way to the present sourceField. As with all other CT's, the Contract State field is used toinfluence the processing of the Contract as it arrives at the recipientCA.

It should be noted that in a modification to the present illustrativeimplementation, the Contract may stop at an intermediate CA if the nextsource side Field does not have a valid Line Segment Limit. In this waythe CT process may be more efficient, allowing a CI to become a CG.Otherwise, CT's must pass through a CI in every Field on the way to thepresent source. CA's at each Field direct and forward the CT, indicatingthe Contract's present processing state, from the CR to the CG and thenback to the CR. It should be noted that the independence of the Coachprocess and the Contract process simplifies, or eliminates the issuesrelated to restoring Contract status for Coaches recovering fromsynchronization failures.

The CR has the primary responsibility to maintain, and possiblydissolve, accepted Contracts. Normally the CR is notified by the Coachthrough the Player when a Contract is no longer required. The CR maythen dissolve the Contract by deleting its local copy and issuing a CTcontaining a “dissolve” status to the CIs and CG, traversing theContract route.

In general, the CR, with the assistance of the CG and all CI's, maintainthe integrity of existing Contracts. This is accomplished by monitoringa Contract's activity timer, Contract Timer, and periodically informingall other CA's of the Contract's presence. To reduce the number ofcommunication transactions necessary to do this, the Timeout of theContract in the CR is set to be shorter than the timeout in CI's or theCG. Thus the CR can notify the CI's and CG of the continued need for theContract and prevent them from having to make unnecessary inquiries.However, if for some reason the CR fails to make the notification, theother CA's can initiate sequences of communication transactions toeither validate the Contract or delete it from their databases.

The CR starts the normal Maintenance Timer by sending a CT (ContractMaintenance Travel) toward the granting CA. The effect of the receipt ofthis transaction at intermediate CA's is to restart the Contract's localtimer, and to forward the Contract Maintenance Travel CT toward theContract Grantor. At the Contract Grantor, the Contract's local timer isrestarted and the maintenance sequence is complete.

In the event that a Contract Maintenance Travel CT is not received byCI's and/or the CG holding local copies of the Contract, the timers willeventually expire. If this happens, the CA will send a CT toward the CRto induce the CR to start its Maintenance sequence. Various errorconditions may occur during this sequence and these are addressed in thelogical flow diagrams FIGS. 56-59 and referenced messages and messagingsequences as will be discussed in more detail hereinafter.

Although the CR has the responsibility to maintain accepted Contracts,the CG and CI's assist in this process by monitoring their maintenancetimers. If a CG or CI's maintenance timer expires, the CA “Tickles” theCR through the CI's (if present), thus attempting to initiate a timermaintenance sequence by the CR.

There are other ways that CI's and the CG assist in the determination ofthe continued validity of a Contract. An example of this would be if aCI, in the process of forwarding the Maintenance Request, determinedthat the source for the circuit had changed. This would most likelyoccur if a normally-open switch along the alternate circuit path hadreopened. That CI would then set the Contract status to “ContractDissolve Start”, thus indicating that the Contract is no longer validand should be dissolved. CT's would then be generated to dissolve theContract.

In another example, an intermediate CA may be able to determine that theline segment limit has already been met, possibly due to segments thathave been added on another branch of the circuit. In this case theintermediate CA can reject the Contract and send it back to the CR.

Upon acceptance of a Contract, all Contract Agents will inform Coachesassociated with Fields along the Contract route of the increase, ordecrease, of required circuit resources. The CA is able to do this basedon the visibility a CA is given into the Fields. To insure the Coachesreceive this information in the most timely manner, the CA will issue anEvent message into the Field. The Event message is delivered to everymember of the Team, allowing the Coach to receive the data at itspresent location, i.e. any player/team member in the team.

Contract Agent Methodology—Logical Flow Illustrations

In accordance with important aspects of the present invention andreferring now to FIGS. 56-59, described therein are illustrative flowdiagram that may be employed and representative of typical operationsperformed by the present invention at each player, e.g. a single teammember. It will be apparent to those skilled in the art that theimplementation of a CA also includes many routine tasks and functions asgenerally discussed hereinafter. For example, any CA activity resultingin the need to send a CT over communications might require a built-indelay or retransmission time to allow a busy communication channel tobecome available. At any time a database or routing table is updated itis possible that the available size of the database or routing tablecould be exceeded. As is typical in such illustrations, in the flowdiagrams of FIGS. 56-59 logical flow is generally from top to bottom(unless otherwise indicated) and where no exit is shown from aprocessing box, this means that the immediate processing of the incomingmessage by the CA has been completed. Also note that a number of thelogical branches in the flow diagrams are annotated with designatedContract States. This means that the branch is conditional on a matchbetween that indicated State(s) and the State found in the CT's ContractState field or the State field of the Contract database entry, whicheverrespective State is being processed. That is, for the flowchart showingthe processing of incoming CT's, the State is the state of the incomingCT, rather than the state of a Contract in the Contract database.

Referring now specifically to FIG. 56, the CA enters its processing loopin processing box 1400 to look for more processing to be performed.Specifically, the CA periodically begins a processing cycle by firstprocessing any incoming CT's received via communications (Yes flow pathto FIG. 57), and then requests for new Contracts from Player tasks inprocessing block 1402 against a local copy of the Contract database (Yesflow path to FIG. 58), and finally in processing block 1404, Contractdatabase entries via flow path to FIG. 59 (based on the contents of theState and Timer data elements). The results of the three types ofprocessing include updating the local Contract database, reporting toPlayer and Coach tasks, and passing CT's along to other CA's whennecessary to secure, maintain, release or reject the Contract, as willbe explained in more detail hereinafter.

Considering now the detailed logical flow regarding the processing ofincoming CT's received over communications and with specific referenceto FIG. 57, illustrated therein is the processing applied to a singleincoming CT, the individual processing blocks being explanatory of theseprocessing steps. The CA processing repeats for each incoming CT. Insome cases this may result in modifications to the local Contractdatabase, and particularly to the Contract State field. The CA then maylater take additional action on the request based on the revisedContract State. This technique is applied throughout the variousContract processing flowcharts to control Contract processing.

FIG. 58 shows the processing applied to incoming Contract processingrequests for a new Contract originating from the local Player task. Ifthe request is to create a new Contract, the Contract data structure iszeroed, initialized with the illustrated data elements and then insertedinto the database. Specifically, in processing block 1406, the Fieldnumber of the Player requesting the additional capacity via Contract isentered in the database. In processing block 1408, the Temp Field dataelement is filled in with the source Field where the capacity is beingsought. This will be one of the adjacent Fields if one exists. Anon-zero (or valid) value in this entry provides additional informationto facilitate the ability of the CA to determine where to send the CT.It should also be noted that the Contract Allocation Mechanism is notselecting from one of several alternate sources, but rather isattempting to allocate a limited resource (distribution capacity) froman energized source specified by the Player when the Contract requestwas issued. As the CT requesting the capacity moves toward a potentialgranting source, each CA will modify the Temp Field to direct therequest toward the present energized source of the circuit. A zero orinvalid entry indicates that the CT has reached the nearest Player andnearest Field to the circuit's source. In processing block 1410, theRequired Quantity and Capacity data elements include the Segment countif capacity restrictions based on segment count (Required Quantity) isbeing requested, and/or capacity restrictions based on load amperage(Capacity). If both are specified, the segment count takes prioritylater when the CA tries to grant capacity to the requestor. TheTimestamp function in processing block 1412 adds a degree of uniquenessto the Contract because it is set only once, here at the CR and nevermodified. If for any reason, a duplicate copy of the Contract appears inthe database, the timestamp can be used to verify the problem. Bysetting the Contract State to “Contract Request Unsent” in processingblock 1414, the CR will (at a later point in processing) see thisContract in the database and send a Contract Request towards the CG.

If the Player is not requesting a new Contract, flow proceeds via the“No” path of the processing block 1405 to the processing block 1416 toprocess a request to terminate an existing Contract. The Contract islocated in the database based on its Contract ID and Field, and itsstatus is modified to be “Contract Dissolve Start”. The CA will, latersend the request to dissolve the Contract towards the CG when itservices the database (explained in more detail hereinafter).

Considering now the processing of Contract database entries at each CAand with reference to FIG. 59, the processing is based on the contentsof the Contract State field with the exception of the Timer managementfunctions. The values of the State field that trigger the specifiedactions are shown as labels on the arrows leading to the processingblocks. Referring now to FIG. 59 a, as discussed, a major activity ofthe CA is to monitor and take action based on the “Contract State” (orState) field of entries in the Contract database. For existing activecontracts (Contract State=Contract Active), this involves starting aContract Maintenance sequence on a predetermined interval, in processingblock 1418. Each CA is monitoring its database's Contract Timers,counting them down, and at this present step in the processing, the CAis looking for an expired timer. Modifying the State to ContractMaintenance Start will subsequently cause the CA to start a maintenancesequence. The “Contract Request Pending” state flow path to processingblock 1420 indicates that a request to initiate a Contract isoutstanding. No further action is taken unless the Contract's localtimer expires, in which case the request is dropped. Since this stateonly appears in the CR, the player is informed that the request hastimed out without being completed. The “Contract Request Unsent” stateflow path to processing block 1422 only occurs at the CR and initiates asequence as shown to travel to a potential CG if not there now, flowpath proceeding via “No” determination path to the process block 1424(FIG. 59 a). If there is no travel required, flow proceeds via the “Yes”determination path to the processing block 1426 since this is apotential CG and either the request is granted or denied based on theavailability of resources.

Referring now to FIG. 59 b, a “Contract Request Travel” database entryindicates that a request is enroute from a CR toward a potential CG,processing block 1428. At each CA along the route, local capacity mustexist to accommodate the additional load (processing block 1428, FIG. 59b). If it does not, the determination in the processing block 1428 is Noand the flow proceeds to the processing block 1430 where the request isrejected by altering its state as shown and returned to the CR. Ifcapacity exists at the CA and it is a source switch nearest thecircuit's ultimate source, flow proceeds via the Yes determination ofthe processing block 1428 to the processing block 1432 where it isaccepted and therefore designated to be the CG, flow proceeding via theYes determination of the processing block 1432 to the processing block1434. Otherwise, flow proceeds via the No determination path of theprocessing block 1432 to the processing block 1436, where thedetermination is made “Is the adjacent source-side Field's sourcedefined.” If Yes, flow will proceed to processing block 1438 to traveltoward the potential CG. If No, flow proceeds to the processing block1440 to decline the request because it has nowhere else to go, againbeing returned to the CR. The “Contract Request Accepted” State isencountered as a notification of a granted Contract being returned tothe CR. This flow for this state proceeds to processing block 1442. Ateach step along the path to the CR, this means that the State should nowbe “Active”, and that it is now time to account for the granted resourceby informing the Coach. If we're at the CR, flow proceeds to aprocessing block 1444 and we do not need to send the message any furtherbut we do need to inform the Player. If we are at the CG or a CI, theflow proceeds to a processing block 1446 where the path to the CRcontinues with appropriate updating and incrementing.

Considering the “Contract Request Declined” and “Declined Continue”states that proceed to a processing block 1448 of FIG. 59 c, thesestates are encountered if the Contract is not accepted. If we're not atthe CR, flow proceeds via the No determination path of the processingblock 1448 to a processing block 1450 where the Declined Continue CT issent toward the CR and the local copy of the Contract is deleted. Ifwe've arrived at the Player, flow proceeds via the Yes determinationpath of the processing block 1448 to a processing block 1452 where thePlayer is notified and the Contract is deleted.

The “Contract Dissolve Start” state proceeds to a processing block 1454and is initiated when a previously existing Contract is no longerneeded. This can be determined and is therefore initiated by a Player atany point along the Contract route of an existing Active Contract. Inparticular, if it is determined that a line segment is no longer beingfed from an alternate source, the Contract is unnecessary. This causes aunique determination in the processing block 1454 to convey the need todissolve the contract in one of two different directions or bothdirections via the processing blocks 1456, 1458 or 1460 dependent uponwhether the determination in the processing block 1454 is CR, CG, or CIrespectively. Once the messages have been sent, the local copy of theContract is deleted and the resources de-allocated via the processingblock 1462.

As shown in FIG. 59 d, the “Contract Dissolve Continue” state,encountered via receipt of a CT requesting that a Contract be dissolved,proceeds to a processing block 1464 If the relative position along theroute as determined in the processing block 1464 is at the CR or CG,terminal points of the route, flow proceeds to a processing block 1466to terminate the communication sequence, deleting the local Contractcopy and requesting the Coach to reduce its contracted reservation ofcapacity. If the relative position is at a CI, flow proceeds to aprocessing block 1468 causing it to forward the CT along the presentroute (up or down) in addition to doing the other steps performed at theCG and CR. The “Contract Maintenance Start” and “Contract MaintenanceTickle Start” States convey the need for the CR to initiate aMaintenance sequence via the flow path to a processing block 1470. Ifthe CR and CG are determined to be the same in the processing block1470, flow proceeds to a processing block 1472 where the Timer is resetand the Contract State is set to Contract Active. If not, flow proceedsto a processing block 1474. If these States are encountered at the CR,the Contract State is set to Contract Active, the Timer is reset and aContract Maintenance Travel CT is sent toward the CG. If these statesencountered at the CG or a CI, the Contract State is set to ContractActive, the Timer is reset and a Contract Maintenance Tickle CT is senttoward the CR to start a Maintenance sequence.

Considering now FIG. 59 e, a “Contract Maintenance Travel” state isentered when a CT was received with that State, and flow proceeds to aprocessing block 1476 where the Contract's maintenance Timer is reset,its State is reset to Contract Active. If not at the CG, the CT isretransmitted toward the CG. If, as this CT is received at a CI or theCG, the Contract is not in the database (shown in FIG. 57, block 1407),a “Contract Maintenance Travel Not Found” state will be substituted withflow proceeding to a processing block 1478. This causes a “ContractMaintenance Travel Return Not Found” CT to be sent back toward the CR,and the local copy of the Contract to be deleted. A “ContractMaintenance Travel Return Not Found” state will be encountered in thedatabase with flow proceeding to a processing block 1480 as the “lostContract” indication is being sent toward the CR. If the database entryis encountered at a CA other than the CR, the Contract is set Active andits timer is reset. If the entry is encountered at the CR, the State ischanged to “Contract Maintenance Reactivate Continue” discussed furtherin connection with FIG. 59 f.

If when attempting to “tickle” the CR into starting a maintenance cycle,the CA determines that the Contract is lost in either the CR or a CIalong the path to the CR, the CA will have inserted a Contract into thedatabase with a State of “Contract Maintenance Tickle Not Found”, flowproceeding to a processing block 1482. This is then deleted and a CTwith State “Contract Maintenance Tickle Return Not Found” is sent towardthe CG. Both of these database entries cause the local copy of theContract to be deleted, and at all CAs other than the one where theContract was discovered missing, the Coach is instructed to release thecontracted resource.

With reference now to FIG. 59 f, initial processing of the “ContractMaintenance Reactivate” and “Contract Maintenance Reactivate Continue”database entries proceeds to a processing block 1484. If we're not atthe CG, flow proceeds to a processing block 1486 where a CT with StateContract Maintenance Reactivate must be sent toward the CG. If we are atthe CG or after the processing block 1486, flow proceeds to a processingblock 1488 where the Contract becomes reactivated by setting its stateto Contract Active and resetting its timer. If the reactivation is beingperformed at any CA other than the CR, the Coach must be informed toallocate (reallocate) the Contracted resource.

Illustrative Example to Secure a Capacity Allocation

The following illustrative example shows how the CA methodology is usedto more-reliably allocate distribution system capacity in a complexpower distribution system. FIGS. 29 through 39 illustrate one example ofhow the logic operated in to reconfigure a complex distribution system,e.g. based on a simple “contract” feature to limit each circuit segmentto one segment of additional load from an adjacent segment. The CAmethodology is not so restricted or limited and instead seeks out andfinds the ultimate source of supply across multiple segments, by beingable to allocate and deallocate more than one segment of additional loadfrom that supply, and by being able to account for the allocation alongthe entire route from load to source. This example is useful toillustrate the CA methodology in the decision making process associatedwith FIG. 29, i.e. closing Switch 20 in Field L, a normally-open switch.Although the Coach in Field K can determine if the Field locally has thecapacity to pick up Field L, it has no way to know if the substation S3has the necessary capacity, i.e. it is assumed and the Coach in Field Lselects its Team member or Player to close Switch 20 because it believesthis is the best alternate source for the circuit. However, neither theCoach in Field L, nor the Coach in Field K, have any way of knowingwhether or not the preferred source has the necessary capacity all theway back to the circuit's source in substation S3 which is severalsegments distant. With CA methodology, the necessary capacity at allpoints along the way to the alternate source will be verified andallocated. By doing so, the CA methodology prevents any potentialcircuit overload that may be caused by the possibility that otherswitches in the distribution system might concurrently close to restoreservice to their own areas of the circuit. The CA methodology alsoovercomes the necessity of the customer to know in advance that eachalternate source can be relied on without regard to the real-timeconfiguration of the distribution system. As discussed, the CAmethodology is operative in the flow of the Player at FIG. 22 b (at theYes output of the processing block “Is Switch Open?” etc.) correspondingto the Switch 20 being open (It's a Source/Tie or Load/Tie switch orother switch which is energized and could serve as an alternate sourceto the circuit), and of course, is presently configured to be part ofthe system. At this point in the logic, the Coach in Field L hasselected Switch 20 as the best source for the Field and so directs thePlayer to attempt to restore power to the Field. The Player in Field Lat Switch 20 would now like to close the switch. At the point in thelogic noted above, the Player requests the CA to determine if theanticipated capacity can be allocated, and to either return that thecapacity exists and has been secured, or to return that the capacitycannot be secured for some reason. If the capacity is contracted, thePlayer will close the switch. If it is not, the Player will inform theCoach which may then attempt to locate and contract for the capacitywith another alternate source.

Referring now to FIG. 56, processing block 1402, the CA at therequesting Player in Switch 20, which is therefore a CR, determines thata new Contract is needed. The logic now moves to FIG. 58, processingblock 1405 and in processing blocks 1406-1414 (excluding block 1407)fills in some details forming what will be the equivalent of a newContract “application”. By setting the Contract State to “unsent”(processing block 1414), the contract, which will be placed in theContract database, will later be recognized as an “application” whichneeds to be processed (forwarded towards a potential CG).

The destination address of the CA in the adjacent Field along the routeto the CG is obtainable from the configuration data base (FIG. 13,Present Source Team Member). In the present implementation, since thereis only one route through energized switches from Switch 20 to theultimate source, S3, the direction of travel of the CT is readilyapparent. However it is not readily apparent that the capacity isavailable at Field I or S3. In addition, Switch 10 in Field G could besimultaneously attempting to pick up load due to an outage affectingField F. It is a feature of the CA methodology to facilitate thisdetermination in a complex, dynamically varying distribution system.

Referring once again to FIG. 22, processing block 1404 and the continuedflow of FIG. 59, the unsent Contract will now be processed by the CR. Atprocessing block 1422, the Contract will be recognized as unsent, andthe CR will determine if the request can be fully satisfied locally orneeds to be communicated to a CA at another location. It should be notedhere that a feature of the CA methodology is that it provides a genericcapability to determine if the necessary capacity exists in a complexdistribution network. By handling local requests as well as thoserequiring communication and coordination with other devices, the CAmethodology serves to simplify the overall resource allocation process.At processing block 1426 in FIG. 59 a, the CR may allocate the resourceand grant the Contract. Doing so will require the CA to notify the Coachbecause the Coach “owns” the amount of available load capacity for theline segment. At processing block 1424, the Contract “application” mustbe forwarded to another CA in an adjacent field, the CR changes theContract State field to “Contract Request Pending”, and also copies theContract “application” to an “outbox”, changing its State to “ContractRequest Travel”. By leaving a copy of the Contract at the CR, with anactivity Timer running, the CR will be able to monitor the as yetunfilled Contract and handle lost Contract “applications”. It should benoted that a requirement of the implementation is to be able to handle awide variety of typical failure modes due to lost communication messagesor processing bottlenecks in such a way as to avoid overloading thecircuit, misallocating resources or losing track of resources such thatthe system is unable to reallocate or redirect the resources at a futuretime.

Considering the next stage of processing, the “Contract Request Travel”message will arrive at the next CA along the path leading from theselected energized source toward the head of the circuit, in this caseit is FIG. 29, Switch 16 in Field K. The logic flow in FIG. 57 at theprocessing block 1409 will add the copy of the Contract, presently in“Contract Request Travel” State, to the database, since the Contract isnew. When the CA inspects the database it will find the Travel messageand process it at processing block 1428 of FIG. 59 b. Note that thelogic at this point requires that there be adequate capacity at thispoint, and every subsequent CA along the route to the alternate source.If not, the Contract is denied. Also note that from this point on, therequest will continue to be routed as a Contract Request Travel messagethrough the system until the message can travel no further and has thusreached the ultimate source switch. In this example, that switch will beSwitch 14 in Field I. When the message reaches that point, the logic atprocessing block 1434 of FIG. 59 b will be executed to accept theContract. This CA is now designated the CG for this Contract.

Along the route from the CR to the CG, the Contract's routing table hasbeen built such that the return path to the CR is known and incorporatedin the Contract. At the CG and in each CI along the route to the CR(processing blocks 1442, 1444 and 1446 of FIG. 59 b), the Contract Stateis set to Contract Active and its maintenance timer is initialized.Also, as the message passes back to the CR, at each device (includingthe CG, the CIs and the CR), the Coach is informed that the Contractedamount of load is now committed to the Contract and is thereforesubtracted from the Field's available capacity.

When the Contract Request Accepted message reaches the CR, in additionto the processing described above, the Player is notified of Contractacceptance and the Player will close the switch to restore the circuitsegment. If for some reason the Contract could not be issued, theContract is declined, the Player and Coach are notified and can eitherattempt to pick up the load from a different source, retry the requestindefinitely or give up trying to restore service.

Overview of Contract Processing Steps

It should be clear from the example above that there are manyeventualities that the CA's must handle as they route the CTs throughoutthe distribution system. Each situation must be processed in such a wayas to minimize the possibility that a circuit is overloaded due toduplicate allocation of resources, the possibility that a field is notenergized because a Contract could not be issued due to a lost CT, orthe possibility that a Contract could not be issued because of a loss ofcontrol over the allocation. These various circumstances are minimizedthrough the application of the processing and rules identified in the CAmethodology flow illustrated in FIGS. 56-59.

The strategy for negotiating, maintaining and dissolving a Contract aresummarized below:

-   1. The Coach on the requesting Field of the transfer event requests    the Player to close an alternate source switch to energize the    Field.-   2. The Player summons the Coach of the granting Field for the    purpose of coordination and verification of circuit resources.-   3. If the Player finds that the transfer restrictions have not yet    been met, and that a Contract is required, the Player issues a    request to the local CA. While the CA attempts to obtain a Contract,    both the requesting Coach and the granting Coach must remain at the    location of the CR, except for an occasional visit to an adjacent    team member to satisfy the visit timer. The Player is also    essentially in a holding pattern while the Contract is being    obtained.-   4. The CR assembles the necessary information into a Contract record    (CA ID, Field number, time, etc.) and sends the record to the CA at    the present source of the granting Field. This requesting CA then    monitors for the return of the record along with its State. After a    predefined period of time, if a response has not been received, the    requesting agent will assume the requested Contract has been lost    (presumably due to communications failure), and will issue a    Declined response back to the Player, ultimately causing the Coach    to reevaluate the selection of the alternate source, and potentially    starting the entire process over again.-   5. The CA receiving the new Contract request evaluates the contents    of the Contract. Since it is a new request the CA verifies that the    circuit resources are available from the perspective of this switch    location. If resources are not available, possibly due to transfers    that are occurring at the same time on a different branch, the CA    flags the Contract as declined and returns it to the origin. If the    Contract is allowed based on local data, the CA adds its ID to the    routing list, and forwards the Contract to the present source team    member of the next Field toward the absolute source.-   6. Assuming that the next CA to receive the new Contract request is    at the source/sub switch this is the point where the Contract will    reside. If adequate circuit resources are not available, the CA    flags the Contract as declined and returns it to the origin using    the now complete routing table. If circuit resources are available    the CA flags the Contract as being accepted, assigns itself as the    granting CA ID, and sends the Contract back toward the origin,    keeping of copy of the Contract locally. The count of circuit    segments that have been transferred is also incremented (see note    below).-   7. Using the Contract routing table the Contract will return to the    next CA going back up the list. This CA will again examine the    contents of the Contract. If the Contract was declined it will    simply continue forwarding the Contract toward the point of origin.    If the Contract was accepted the CA will store a copy of the    Contract in its local Contract database, and increment the local    allocation for the amount of load that have been transferred. The    allocation of resources then, stored within the Coach's data (e.g.    like a briefcase), can be used to make immediate decisions regarding    additional transfers that may be requested. The Contract will then    again be forwarded toward its origin.-   8. Assuming that the next CA to receive the Contract is at the point    of origin, if the Contract was flagged as Declined the CA will    report back to the Player that the transfer is not allowed. The    Contract will then dissolve. If the Contract was flagged as accepted    the CA will report back to the Player that the transfer may continue    as normal, allowing the desired switch to close. The Contract is    then stored locally, and the allocation of resources is incremented.-   9. Once a Contract is stored in the CA's database it must be    maintained. Maintenance of the Contract is normally only initiated    by the CR, although a CI may “tickle” the requesting agent for    maintenance if the Contract appears to be getting stale. A    maintenance timer is associated with each Contract, with the CR    having a shorter time interval than other CAs. When the timer    expires the CR will send a copy of the Contract, marked as    Maintenance Travel, toward the CG.-   10. A CI receiving this maintenance request will look for the    Contract in its database, and if found will update the local    maintenance timer associated with that Contract, then forward the    maintenance request (Maintenance Travel) toward the CG. If the    Contract is not found in the local database, the CA will return the    Contract back to the CR flagged as not found (Contract Maintenance    Travel Return Not Found). Upon receiving the indication of Contract    not found, the CR may reactivate the Contract by issuing the    Contract again and propagating the reactivation toward the CG    (Contract Maintenance Reactivate). Any CA still holding the original    Contract will just forward the reactivation message. Any CA without    the Contract will accept the Contract immediately and again    increment its local resource allocation as necessary, then forward    it again toward the CG.-   11. If a CA other than the CR finds that a Contract maintenance    timer has expired for an active Contract, that CA will send a    “tickle” Contract message to the requesting agent. This function is    intended to prevent a Contract from remaining in place for an    extended period unnecessarily. The reception of the “tickle”    Contract message at the CR signals the requesting agent to start a    Contract maintenance cycle.-   12. If a “tickle” Contract message routed to the CR is received by    an agent with no matching Contract, a Contract Maintenance Tickle    Return Not Found message is propagated back toward the CG. As the    Contract travels it is removed at each location where it still    exists, and the appropriate adjustments are made to the local    resource allocation. If the Contract was actually still required by    the CR, a subsequent maintenance process from the CR will result in    a Contract reactivation process (Contract Maintenance Reactivate).-   13. While in an alternative embodiment discussed hereinafter the CA    may find a reason for the Contract to be dissolved, presently    automatic operation by the Coach and Player may result in the Player    immediately asking for the removal of the Contract. This would    likely be the result of a Return-to-Normal operation being performed    locally, but may also be a second contingency event that causes    additional reconfiguration of the circuit. Again in this case, the    CA flags the Contract to be dissolved and forwards it down the    Contract route. The Contract is then removed by each CA, and all    appropriate actions are taken to restore the resource restrictions    for the next transfer event. Incrementing and decrementing the local    allocation of resources is performed at this point in the flow. The    allocation of resources then, stored within the Coach's data (e.g.    like a briefcase), can be used to make immediate decisions regarding    additional transfers that may be requested.

Considering such an alternative embodiment, a task is included for therequesting CA to watch for any reason to dissolve the Contract directly.For example, a manual switching operation that moves this circuitsegment to another source would be grounds to dissolve the Contract.This may be a manual operation on the Field that was the origin of theContract, or a manual operation at another Field seen locally only bythe clearing of the alternate source flag. The Contract would then bedissolved in accordance with the foregoing discussion.

In accordance with another alternative embodiment, capacity istemporarily allocated as the CT traverses intermediate line segmentsthat may be limiting segments. A timer is assigned to the temporaryallocation such that if the Contract is not granted, the temporaryallocation is assured of eventually being utilized or deleted. Thiswould account for the remote possibility where two Contracts have beensent to a common CG upstream from a CI with the two Contracts requiringcapacity at an intermediate line segment, which, in combination, exceedsits capacity.

While there has been illustrated and described various embodiments ofthe present invention, it will be apparent that various changes andmodifications will occur to those skilled in the art. Accordingly, it isintended in the appended claims to cover all such changes andmodifications that fall within the true spirit and scope of the presentinvention.

1. In an electrical power distribution system having a plurality ofdefined nodes at points along the distribution system, a methodology forallocating system resources via resources at each node for determiningresource allocation requirements and communications of source allocationmessages to other nodes to request and establish an appropriateallocation of system resources.
 2. The system of claim 1 wherein theallocation of system resources includes the prevention of overloading ofsystem power sources.
 3. The system of claim 2 wherein the sourceallocation messages include information representing a request forsource allocation evaluation and reservation.
 4. In an electrical powerdistribution system having a plurality of defined nodes at points alongthe distribution system, a system for allocating system sourcescomprising: first resources at predetermined nodes for determiningsource allocation requirements; and means for communicating sourceallocation messages to other nodes to request and establish anappropriate allocation of system sources.
 5. The system of claim 4further comprising autonomous distribution control devices located atpredetermined ones of the nodes for controlling the flow of electricalpower through the system.
 6. A method for responding to abnormalities ina commodity distribution system having two or more teams of commoditycontrol devices, the method comprising the steps of: communicatinginformation between teams via communication between individual teammembers, the information representing additional information on how torespond to particular detected conditions, one or more team members of afirst team responding to detected conditions based on informationcommunicated from a second team, the communicated informationrepresenting task identifiers and the status of detected systemconditions external to the first team.
 7. A method for responding toabnormalities in a commodity distribution system having two or morecommodity sources and two or more teams of commodity control devices,the method comprising the steps of: communicating information betweenteams via communication between individual team members, the informationincluding functional representations of tasks to respond to detectedconditions based on a negotiated plan between teams, a first team actinglocally based on the information received from a second team thatrepresents additional information on how to respond to particulardetected conditions, one or more team members of a first team respondingto detected conditions based on information communicated from a secondteam, the communicated information representing commodity sourceallocation data.
 8. A system including first resources at nodes andsecond resources communicated between and used by said first resourcesto respond to and act on communicated information to reconfigure thesystem in response to detected conditions.
 9. A system for automatedreconfiguration of a distribution system, comprising: a plurality ofswitches, switches in the plurality of switches being located in thedistribution system; and a plurality of switch controllers; switchcontrollers in the plurality of switch controllers controllingrespective switches in the plurality of switches and including firstresources which monitor the distribution system and respond topredetermined abnormalities; and second resources communicated betweenand exchanging information with said switch controllers and determiningwhether to operate respective switches to perform reconfiguration of thedistribution system.
 10. A method for controlling the configuration ofan electrical power distribution system having a plurality ofdistribution devices including circuit opening and closing functions,the method comprising the steps of: responding to detected conditionsrequiring reconfiguration of the system; communicating informationbetween the plurality of distribution devices; at least one of theplurality of distribution devices communicating with at least one deviceexternal to the plurality of switch controllers to obtain additionalinformation about the condition of the system that is used to controlreconfiguration; and controlling operation of the plurality ofdistribution devices to reconfigure the electrical power distributionsystem based on the information communicated between the plurality ofdevices and the additional information obtained from the at least oneexternal device.
 11. A system for controlling the configuration of anelectrical power distribution system comprising: a plurality ofdistribution devices including circuit opening and closing functions;and control means responding to detected conditions requiring areconfiguration of the system, communicating with at least one deviceexternal to the plurality of switch controllers to obtain additionalinformation about the condition of the system that is used to controlreconfiguration, communicating information between the plurality ofdistribution devices, and controlling operation of the plurality ofdistribution devices to reconfigure the electrical power distributionsystem.